Session 145 Cataract surgery_ Optimizing IOL selection

Transcription

ARVO 2016 Annual Meeting Abstracts
145 Cataract surgery: Optimizing IOL selection, surgical
procedures, and training
Sunday, May 01, 2016 1:30 PM–3:15 PM
Exhibit/Poster Hall Poster Session
Program #/Board # Range: 912–946/D0274–D0308
Organizing Section: Lens
Program Number: 912 Poster Board Number: D0274
Presentation Time: 1:30 PM–3:15 PM
Evaluation of the IOLMaster 700
Mark A. Bullimore1, Derek Le1, Gabriel Leche1, Paul Stanley1,
Paul Yoo2, Todd Otani2. 1University of Houston, Boulder, CO; 2Carl
Zeiss Meditec, Inc., Dublin, CA.
Purpose: Optical biometry, based on partial coherence
interferometry, is the gold standard for for obtaining precise
ocular measurements. The Carl Zeiss Meditec IOLMaster 700
utilizes a newer swept-source OCT technology to obtain all axial
measurements, including axial length, anterior chamber depth,
corneal thickness, and lens thickness. We evaluated the repeatability
and reproducibility of the IOLMaster 700 and its agreement with the
IOLMaster 500 and Lenstar LS900.
Methods: Complete biometric measurements were taken on one
eye chosen at random of 100 subjects, 51 of whom manifested
cataracts (47 to 85 years, BCVA 20/16 to 20/80) and 49 of whom
had clear lenses (22 to 58 years). Among the full cohort, there were
42 eyes with corneal astigmatism ≥ 0.75 D. Three sets of biometric
measurements were taken by three operators with three different
IOLMaster 700 units, and one operator took three measurements
with the IOLMaster 500 and the Lenstar LS 900. A random effects
model of analysis of variance (ANOVA) was used to estimate the
repeatability and reproducibility. The 95% limits of agreement (95%
LoA) were calculated for all comparisons using the first acceptable
measurements from each instrument.
Results: Comparing the IOLMaster 700 and IOLMaster 500 in
cataract patients, 95% LoA were –0.01 to +0.06 mm for axial length,
–0.44 to +0.27 D for mean corneal power, and –0.18 to +0.17 mm
for anterior chamber depth. Likewise, a comparison between the
IOLMaster 700 and the Lenstar LS 900 for corneal thickness and
lens thickness yielded 95% LoA of –4 to +13 µm and –0.26 to +0.41
mm, respectively. The repeatability and reproducibility limits for the
IOLMaster 700 in cataract patients were ±0.014 and ±0.023 mm for
axial length; ±0.26 and ±0.27 D for mean corneal power; ±7 and ±11
µm for corneal thickness; ±0.02 and ±0.02 mm for anterior chamber
depth; and ±0.02 and ±0.05 mm for lens thickness. For comparison,
the repeatability limits in cataract patients were ±0.043 mm for axial
length, ±0.24 D for mean corneal power, and ±0.15 mm for anterior
chamber depth for the IOLMaster 500, and ±7 µm for corneal
thickness and ±0.27 mm for lens thickness for the Lenstar.
Conclusions: There was good agreement between the IOLMaster 700
and the comparative instruments and superior or equivalent precision.
While some statistically significant differences were noted for axial
length and mean corneal power, these would not be considered
clinically meaningful.
Commercial Relationships: Mark A. Bullimore, Alcon
Laboratories (C), Innovega (C), Carl Zeiss Meditec (C), Genentech
(C); Derek Le, None; Gabriel Leche, None; Paul Stanley, None;
Paul Yoo; Todd Otani, Carl Zeiss Meditec
Evaluation of a new noncontact biometer IOLMaster 700 ®
compared to Lenstar®
Hussam El Chehab, Emilie Agard, Apolline Mairot, Amélie Lefevre,
Aurélie Russo, Corinne Dot. Ophthalmology, Hospital Of
Desgenettes, Lyon, France.
Purpose: Since phacoemulsification became a refractive surgery,
accuracy of power calculation of intraocular lens (IOL) is essential.
The aim of this study is to compare two non contact biometers,
IOLMaster700® (Carl Zeiss, Germany) recently commercialized was
compared to Lenstar® (Haag-Streit, Switzerland).
Methods: This prospective study included patients referred to our
center for cataract surgery in June 2015. They benefited measurement
with IOLMaster700® and Lenstar®. We compared and analyzed the
correlations between the different biometric eye parameters (axial
length -AL-, mean keratometry, central corneal thickness, anterior
chamber depth -ACD- from epithelium, crystalline lens thickness
and the white to white distance). The IOL power calculated with
the SRK/T and Haigis formulas was analyzed. We compared data
by a paired t-test and correlations were evaluated by the Pearson
correlation coefficient.
Results: 129 eyes of 129 patients were included (50.8% female). The
failure rate was 0.7% for both devices.
Concerning the biometric data, there is a statistically significant
difference in measurements of white to white distance
(11.97mm±0.07 with IOLMaster700 vs. 12.06mm±0.07 for Lenstar,
p<0.001) as well as the ACD (3.06±0.07 mm with IOLMaster700
vs. 0.07 ± 3.07mm for Lenstar, p<0.001). Others measures (AL and
keratometry) wasn’t statistically different between the two devices.
With SRK/T formula, IOL power isn’t different (20.94D±0.51 for
IOLMaster700 vs. 20.92D±0.50 for Lenstar, p=0.51). With Haigis
formula, IOL power was statistically different between the two
devices (21.04D±0.52 with IOLMaster700 vs. 20.84D±0.52 for
Lenstar, p<0.01). In 31.25% of cases, calculated IOL was different
between the two biometers, with the formula SRKT and 52.34% with
the Haigis formula. There wasn’t a significant difference in refractive
errors between the two machines regardless of formula.
The correlations between the two devices for all data are high.
Highest Pearson coefficient is for axial length (r=1, p<0.01), Lowest
is for the white to white distance (r=0.81, p<0.01).
Conclusions: The measurements with both devices have a very
good correlation. The implant calculation between the two devices
differ in 31 to 52% of cases by the formula selected, which can be
disadvantageous in case of multifocality. A study on postoperative
refractive results would determine the custom constants to reduce the
postoperative refractive error.
Commercial Relationships: Hussam El Chehab, None;
Emilie Agard, None; apolline mairot, None; Amélie lefevre, None;
Aurélie Russo, None; Corinne Dot, None
Comparison of predictive accuracy and tendency of 4 intraocular
lens calculation formulas using a new optical biometer (IOL
Master 700) depends on 3 common intraocular lens and
biometric factors
Takeshi Teshigawara1, 2, Akira Meguro3, Takuto Sakono3,
Nobuhisa Mizuki3. 1Yokosuka Chuoh Eye Clinic, Yokosuka, Japan;
2
Tsurumi Chuoh Eye Clinic, Yokohama, Japan; 3Department of
Ophthalmology, Yokohama City University School of Medicine,
Yokohama, Japan.
These abstracts are licensed under a Creative Commons Attribution-NonCommercial-No Derivatives 4.0 International License. Go to http://iovs.arvojournals.org/
to access the versions of record.
Purpose: To evaluate accuracy and tendency of prediction by 4
intraocular lens (IOL) calculation formulas using a new optical
biometer (IOL Master 700, Carl Zeiss Meditec) depends on 3
common IOLs, AMO Tecnis 1 ZCB00V (ZCB), STAAR KS-SP (KS),
Alcon SN60WF (SN), and biometric factors.
Methods: This retrospective study used 253 eyes (71 ZCB, 100 KS
and 82 SN). Using IOL Master 700, 3 preoperative parameters, axial
length (AL), anterior chamber depth (ACD) and keratometry (K),
were measured. Preoperative IOL power calculations were done with
4 formulas, Haigis (HG), SRK/T (S/T), HofferQ (HQ) and Holladay2
(H2). Mean absolute estimation error (MAE) and mean postoperative
refraction shift (MPRS) were compared, and correlation between
postoperative refraction shift (PRS) and the parameters were analyzed
among combinations of each formula and each IOL. Wilcoxon
signed-rank test, Paired T test and Spearman’s rank correlation were
used to analyze accordingly.
Results: In ZCB, MAE was significantly lower in S/T and H2
compared to HQ (p<0.01). In KS, MAE was significantly higher in
HG compared to other formulas (p<0.0001). In SN, no significance
in MAE was shown among formulas. In ZCB, MPRS showed
significant hyperopic shift in HG and HQ compared to H2 showing
slight hyperopic shift (p<0.0001). In KS, MPRS showed significant
myopic shift in S/T compared to other formulas showing hyperopic
shift (p<0.0001). In SN, MPRS showed significant hyperopic shift in
S/T compared to other formulas showing myopic shift (p<0.0001).
In ZCB and SN, significantly positive correlation between PRS and
AL was observed in HQ and H2 (r>0.3 p<0.01). In ZCB, significantly
positive correlation between PRS and ACD was observed in S/T, HQ
and H2 (r>0.3 p<0.01). In SN, the same was true in S/T and HQ. In
each IOL, positive correlation between PRS and K in HG and HQ,
and negative correlation between them in S/T and H2 was observed.
Especially, the significance (p<0.01) was observed in HG (r>0.3)
and S/T (r<-0.3) using each IOL, in HQ (r>0.3) using KS, and in H2
(r<-0.3) using SN.
Conclusions: Accuracy and tendency of prediction by the formulas
using IOL Master 700 varies depending on the IOLs. The parameters
can also influence tendency of prediction in different ways.
Conversance to these factors is vital to improve prediction of IOL
calculation.
Commercial Relationships: Takeshi Teshigawara, None;
Akira Meguro; Takuto Sakono, None; Nobuhisa Mizuki, None
The Magic Cube: Comparison of Three Third Generation
Formulas on Three Intraocular Lens Calculators, IOL Master,
DGH 6000 and UniversIOL
Ahmad Al-Heeti1, Stephan Leibbrandt2, 1, Samir I. Sayegh1.
1
Ophthalmology, The EYE Center, Champaign, IL; 2Symbols and
Number, Aachen, Germany.
Purpose: While it is generally assumed that different devices will
produce the same output for a given formula and that the third
generation formulas results may differ mainly for extreme axial
lengths, it is legitimate to question these assumptions. The goal
of this study is to compare IOL power results for emmetropia for
SRK/T, Hoffer Q and Holladay I formulas using the IOLMaster,
DGH 6000 A-scan biometer, and UniversIOL calculators.
Methods: Eyes with axial lengths ranging from 20 to 30mm with
increments of 0.5 mm and mean corneal powers ranging from 38
to 50 diopters (D) with increments of 0.5 D generated a set of 525
cases that were entered in each calculator for each device with a
target refraction of plano. SRK/T A constant was 119, HofferQ
pACD constant 5.64 and Holladay I surgeon factor, 1.84. IOL power
calculation according to these formulas were obtained using the
IOL Master (IOL Master 500), A scan (DGH6000) and UniversIOL
universal calculator.
Results: The mean absolute difference between all three formulas
was less than 1/50 D on all three calculators. For Holladay 1 and
Hoffer Q the maximum absolute difference between calculators
results did not exceed 0.1 D for any combination of axial length and
mean corneal power, and with the exception of a zone in parameter
space where the corneal height square root approaches zero, SRK/T
yielded similar results. Results for comparison between formulas
confirmed the known dependence and differences depending on axial
length but revealed a persistent non physiological “cusp” in all three
implementations with UniversIOL calculation being closest to the
physiological result.
Conclusions: Implementation of third generation formulas in
multiple calculators on different platforms are consistent, with some
rare but clinically relevant exceptions that are detailed. Differences
between formulas are consistent with generally accepted axial length
dependence recommendations but also differ in areas less often
recognized. These differences can be manually/visually inspected
by the surgeon on all three calculators considered and automatically
flagged in UniversIOL.
Commercial Relationships: Ahmad Al-Heeti, None;
Stephan Leibbrandt; Samir I. Sayegh, None
Relative Impact of Biometric Variables on Intra-Ocular Lens
Calculations in the Setting of Newer Generation Formulae
Alexander A. Foster1, Jason Kam2, Hoon Jung2. 1School of Medicine,
University of Washington, Anchorage, AK; 2Department of
Ophthalmology, University of Washington, Seattle, WA.
Purpose: The accuracy of the Holladay 2 (H2) formula has been well
documented to improve refractive outcomes for cataract surgery. The
derivations of such formulae remain unspecified due their proprietary
nature. Use of additional biometric parameters to enhance outcomes
is reported to be one source of improvement over previous formulae.
This exploratory study looks to identify relative importance of
various biometric parameters on intraocular lens calculations and
also cite places for potential human error input as more variables are
included in every increasingly complex formulae.
Methods: Four adult volunteers were imaged with IOL Master 500
(Zeiss) containing H2 Formula. We selected the TECNIS ZCB00
lens. The study population included one high myope with history
of bilateral photorefractive keratectomy, one high myope with mild
cataract, one mild myope and one hyperopic volunteer. Attention
was given to seven modifiable biometric variables of interest: Axial
Length (AL), Keratometry (K), Horizontal White To White (WTW),
Anterior Chamber Depth (ACD), Manifest Refraction (MRx), Lens
Thickness (LT) and Age of subject (A). Each of these variables were
manually and independently modified with a subsequent derivation of
change in recommended IOL averaged across all patients.
Results: For each one mm change of AL, there was 1.625D change
in recommended IOL power. For each 1D change of average K, there
was a 1.12D change of IOL power. For the allowed range of manual
input of ACD (1-8 mm) there was an average maximum effect of
1.18D. For the allowed range of input of WTW (8.5-15 mm) there
was an average maximum 0.79D potential error. For the allowed
range of MRx max/min (-25D to +15D) spherical equivalent had
a maximum average 2.64D change. For the allowed range or LT
(1-9mm) had a maximum 0.7D of effect. On average, changing the
age by 50 years changed the recommended IOL power by -0.345D.
Conclusions: Each input variable is important and has potential
to alter recommended IOL power. Independently, the order of
significance would be AL, K, ACD, WTW, MRx, LT and A
respectively. In the context of increasingly complex newer generation
formulae, this analysis gives general insight on the significance of
various bioparameters independently. Further in depth analyses with
changing multiple variables would further elucidate the importance of
accuracy in measurement devices as well as user input.
Commercial Relationships: Alexander A. Foster, None;
Jason Kam, None; Hoon Jung, None
The end of preoperative biometry? Calculating intraocular
lens power ‘on the table’ with two new intraoperative HartmannShack aberrometry derived formulae
Jan O. Huelle2, 1, Vasyl Druchkiv1, Nabil Habib2, Gisbert Richard1,
Toam Katz3, 1, Stephan Linke1, 4. 1Department of Ophthalmology,
University Medical Center Hamburg-Eppendorf, Hamburg,
Germany; 2Ophthalmology residency rotation, South West Peninsula
Postgraduate Medical Education, Plymouth, United Kingdom;
3
Universitätsklinikum Hamburg-Eppendorf, Care Vision, Hamburg,
Germany; 4zentrumsehstärke, Hamburg, Germany.
Purpose: To explore the application of intraoperative wavefront
aberrometry (IWA) for aphakia based biometry introducing two new
improved formulae. Further, to evaluate challenges to IWA presented
by multifocal intraocular lens implants (mIOL). To test the recently
postulated hypothesis that IWA outperforms conventional biometry.
Methods: During routine cataract surgery on 69 eyes (mean age
69.39±11.39 years), three repeated measurements of aphakic
spherical equivalent (SE) were taken. All measurements were
objectively graded for their quality and evaluated with the ‘limits of
agreement’ approach. Odds ratios and ANOVA were applied. The
IOL that would have given the target refraction was back-calculated
from postoperative manifest refraction at 3 months. Regression
analysis was performed to generate two aphakic SE based formulae
to predict this IOL. The accuracy of the formulae was determined by
comparing them to conventional biometry and to published aphakia
formulae. Results were compared to 10 additional patients (mean age
55.87±11.89 years) who received a mIOL implant.
Results: In 41% of patients, three consecutive aphakia measurements
were successful. Objective parameters of IWA map quality
significantly impacted measurement variability (p<0.05). The limits
of agreement of repeated aphakic SE readings were +0.66 dioptre
(D) and -0.69D. Intraoperative biometry by our formula resulted
in 25% and 53% of all cases ±0.50D and ±1.00D within target,
respectively. A second formula taking axial length into account
yielded corresponding ratios of 41% and 70%, respectively. The
median absolute errors of prediction for our second formula and
for conventional biometry were significantly different with 0.65D
and 0.44D, respectively (p<0.05). Compared to the mIOL group,
measurement success in pseudophakia was lower, IWA map quality
significantly lower (p< 0.05) and accuracy of IOL calculation higher.
Conclusions: Inconsistent with the hypothesis, a reliable application
of IWA to calculate IOL power during routine cataract surgery may
not be feasible given the high rate of measurement failures and
the large variations of successful readings. To enable reliable IOL
calculation from IWA, measurement precision must be improved
and aphakic IOL formulae need to be fine-tuned. Pseudophakic IWA
measurements with mIOLs must be interpreted with caution.
Commercial Relationships: Jan O. Huelle, None; Vasyl Druchkiv,
None; Nabil Habib, None; Gisbert Richard, None; Toam Katz,
None; Stephan Linke, None
Accuracy of intraocular lens power calculation formulas for
highly myopic eyes
Yichi Zhang1, Xiao Ying Liang2, Shu Liu3, Jacky W. Y. Lee2, 3,
Srinivasan Bhaskar3, Dennis S.C Lam1, 3. 1State Key Laboratory
of Ophthalmology, Zhongshan Ophthalmic Center Sun Yat-sen
University, Guangzhou, China; 2Dennis Lam & Partners Eye Center,
Hong Kong, China; 3C-MER (Shenzhen) Dennis Lam Eye Hospital,
Shenzhen, China.
Purpose: There are always unexpected hyperopic outcomes with
intraocular lens (IOL) power calculation formulas for high myopia
and still unclear which formula is more suitable for high myopia. We
performed a retrospective study to evaluate and compare the accuracy
of different IOL power calculation formulas for eyes with an axial
length (AL) greater than 26.00 mm.
Methods: This retrospective study reviewed 407 eyes of 219 patients
with AL longer than 26.0 mm. The refractive prediction errors (the
difference between the actual postoperative refractive outcome and
the predicted refraction) of IOL power calculation formulas (SRK/T,
Haigis, Holladay, Hoffer Q, Barrett Universal II) using User Group
for Laser Interference Biometry (ULIB) constants were evaluated and
compared. Eyes were divided into groups by using plus-power, zerodiopter and minus-power IOLs.
The differences in the MNE, MAE, and median absolute error
between formulas were assessed using the Wilcoxon signed-rank test.
The Bonferroni correction was used for multiple comparisons. The
association between refraction prediction error and AL were assessed
using Spearman’s rank correlation. P-values less than 0.05 were
considered statistically significant.
Results: Two hundreds eighty-eight eyes of 183 patients were
enrolled, the mean AL was 29.17 ± 2.46 mm; these included 265
eyes with plus-power IOL (Group A), 22 eyes with minus-power IOL
(Group B), and 1 eye with zero-diopter IOL. In Group A, SRK/T,
Haigis, Barrett Universal II formulas had similar Mean Absolute
Error (MAE), but statistical difference was seen with Holladay and
Hoffer Q formulas (p<0.005) (Table 1). In Group B, there were no
statistical differences between all formulas, but the inter-quartile
range and MAE of the Barrett Universal II formula were the lowest
among all the formulas (Table 1 and Table 2), and this formula
yielded the highest percentage of eyes within ±0.5 D and ±1.0 D of
the target refraction (Figure).
Conclusions: For high myopic eyes with plus-power IOL, the
SRK/T, Haigis, Barrett Universal II formulas had similar predictive
outcome. For eyes with minus-power IOL, the Barrett Universal II
formula may be a more suitable choice.
Comparison of six IOL power calculation formulas in eyes with
axial length ≤22 mm
Li Wang1, Sabite Gokce1, John Zeiter1, Mitchell P. Weikert1,
Warren Hill2, Douglas D. Koch1. 1Cullen Eye Institute, Baylor
College of Medicine, Houston, TX; 2East Valley Ophthalmology,
Mesa, AZ.
Purpose: To compare the accuracy of refractive prediction of six IOL
power calculation formulas in eyes with axial length (AL) ≤22 mm.
Methods: We evaluated six IOL power calculation formulas: 4
standard formulas (Holladay 2, Holladay 1, Hoffer Q, and Haigis)
and 2 newer formulas (Olsen and Barrett). Consecutive cases that
had cataract surgery from January 2011 to November 2015 with
AL ≤22 mm were reviewed. Inclusion criteria were: 1) biometric
measurements with Lenstar (Haag-Streit AG), 2) no previous ocular
surgery or intraoperative or postoperative complications, and 3)
postoperative best-spectacle corrected visual acuity of 20/30 or
better at 3 weeks or longer. The refractive prediction error (RPE) was
calculated as the difference between the actual refractive outcome
postoperatively and the predicted refraction using each formula.
Lens constants in each formula were optimized. The median absolute
refractive prediction error was calculated.
Results: In 77 eyes, for Holladay 2, Holladay 1, Hoffer Q,
Haigis, Olsen and Barrett, respectively, the mean RPE values were
-0.31 ± 0.47 D, -0.03 ± 0.50 D, -0.21 ± 0.49 D, -0.09 ± 0.54 D,
-0.03 ± 0.49 D, and +0.28 ± 0.50 D; the mean RPEs with Holladay
2, Hoffer Q, and Olsen were significantly different from zero (all
P<0.05). The median RPE values were 0.38 D, 0.38 D, 0.39 D,
0.41 D, 0.39 D, and 0.41 D, respectively, there were no significant
differences among formulas (P>0.05); % of eyes within 0.5 D and 1.0
D of RPE were 71% and 97%, 73% and 97%, 68% and 99%, 64%
and 90%, 70% and 95%, and 64% and 95%, respectively, there were
no significant differences among formulas (P>0.05).
Conclusions: There were no significant differences among the
standard and newer formulas in short eyes. Further studies exploring
factors contributing to refractive prediction errors are desirable.
Commercial Relationships: Li Wang, None; Sabite Gokce, None;
John Zeiter, None; Mitchell P. Weikert, None; Warren Hill, None;
Douglas D. Koch, Revision Optics (C), Alco (C), Abbott Medical
Optics (C)
Support: Research to Prevent Blindness
Commercial Relationships: Yichi Zhang, None; Xiao Ying Liang,
None; Shu Liu, None; Jacky W. Y. Lee; Srinivasan Bhaskar, None;
Dennis S.C Lam, None
Support: 985 project (No.83000-52121200) and 1000 Plan Grant by
Chinese Government (No. 83000-42020002)
Comparison of Preoperative Intraocular Lens Power Selection
Methods to Intraoperative Aberrometry in Eyes with Axial
Myopia
Christopher S. Hill1, Darren Hill1, Shruti Sudhakar1, Ingrid U. Scott1,
Brett Ernst2, Seth Pantanelli1. 1Ophthalmology, Penn State Hershey
Medical Center, Hummelstown, PA; 2Schein Ernst Mishra Eye,
Harrisburg, PA.
Purpose: To compare the SRK/T, Holladay1, and Wang-Koch
axial length (AL) optimized Holladay1 formulas to intraoperative
aberrometry (Alcon ORA) with respect to accuracy in predicting
residual refractive error after cataract surgery in eyes with axial
myopia.
Methods: Retrospective comparative case series including 51 eyes
with AL>25.0 mm that underwent cataract extraction with intraocular
lens (IOL) implantation. Eyes were ineligible for the study if
they had previous ocular surgery or trauma, ocular inflammatory
conditions, vision-limiting retinal or optic nerve disease, unreliable
optical biometry data, a complication during cataract surgery, a target
postoperative refraction other than emmetropia, lack of follow-up,
or a postoperative best-corrected visual acuity worse than 20/40.
For each eye, the 1-center Wang-Koch AL-optimized Holladay1
formula was used to select an IOL that targeted emmetropia. Residual
refractive error was also predicted pre-operatively using the SRK/T
and Holladay1 formulas and intraoperatively using the ORA.
Refraction was measured 4-6 weeks postoperatively and compared to
the three preoperative and intraoperative prediction methods.
Results: The mean residual refractive error (spherical equivalent)
of the study population was 0.012 +/1 0.411 D (range: -0.875 D to
1.250 D). The mean numerical error (MNE) associated with using
the SRK/T, Holladay1, AL-optimized Holladay1, and ORA were
0.204 +/- 0.420, 0.330 +/- 0.463, -0.022 +/- 0.383, and 0.055+/0.396 D, respectively (p<0.0001). Prediction error was significantly
less with the AL-optimized Holladay1 and ORA than with the
unmodified Holladay1 formula. The proportion of patients within
0.5 D of predicted was 74.5%, 60.8%, 82.4%, and 80.4% using the
SRK/T, Holladay1, AL-optimized Holladay1, and ORA, respectively
(p=0.096). Hyperopic outcomes occurred in 70.6%, 76.5%, 49.0%,
and 45.1%, respectively (p=0.001). AL-optimized Holladay1 and
ORA yielded significantly fewer hyperopic outcomes than the
unmodified Holladay1 formula.
Conclusions: The AL-optimized Holladay1 formula and ORA were
more accurate than the unmodified Holladay1 formula in predicting
residual refractive error after cataract surgery in eyes with axial
myopia. The AL-optimized Holiday1 and ORA are equally effective
in reducing MNE and hyperopic outcomes.
Commercial Relationships: Christopher S. Hill, None;
Darren Hill, None; Shruti Sudhakar, None; Ingrid U. Scott, None;
Brett Ernst, None; Seth Pantanelli, None
Comparison of Preoperative Intraocular Lens Power Selection
Methods to Intraoperative Aberrometry in Short Eyes
Shruti Sudhakar1, Darren Hill1, Christopher Hill1, Ingrid U. Scott3, 4,
Brett Ernst2, Seth Pantanelli3. 1Penn State University, Hershey, PA;
2
Schein Ernst Mishra Eye, Harrisburg, PA; 3Ophthalmology, Penn
State University, Hershey, PA; 4Public Health Sciences, Penn State
University, Hershey, PA.
Purpose: Lens selection algorithms work well for normally sized
eyes, but for patients with short eyes (axial length ≤ 22mm), these
equations are far less accurate. The purpose of this retrospective
case series is to compare the accuracy of the Hoffer Q, SRK/T, and
Holladay1 formulae to that of intraoperative aberrometry (Alcon
ORA) with respect to predicting residual refractive error after cataract
surgery in eyes with short axial length to reveal the best method for
lens selection.
Methods: For all eyes with an axial length ≤ 22.0 mm that underwent
cataract surgery by two surgeons between November 2014 to
August 2015, predicted residual refractive error was calculated
preoperatively using the Hoffer Q, SRK/T, and Holladay1 formulae
and intraoperatively using the Alcon ORA aberrometer before IOL
implantation. These predictions were used to select an intraocular
lens (IOL) with a postoperative refractive target of emmetropia.
Refraction was measured between 4 and 8 weeks postoperatively and
compared to the preoperative and intraoperative prediction models
for the selected IOL.
Results: Eleven eyes of 11 patients were identified with an axial
length ≤ 22.0 mm. Axial lengths ranged from 20.37 to 21.94 mm,
with a mean of 21.59 mm. The mean numerical errors (MNE)
associated with the Hoffer Q, SRK/T, and Holladay1 formulae and
ORA were 0.036 +/-0.703 D, 0.239 +/- 0.731, 0.147 +/- 0.697 D,
and 0.063 +/- 0.595, respectively (p-value > 0.05). Additionally, the
mean absolute errors (MAE) were 0.586 +/- 0.343, 0.585 +/- 0.469,
0.519 +/- 0.456, and 0.440 +/- 0.371, respectively (p-value > 0.05).
The proportion of patients within 0.5D of target refraction was
36.4%, 63.6%, 55.6%, and 63.6%, respectively (p-value > 0.05).
Conclusions: No significant difference was identified among the
Hoffer Q, SRK/T, and Holladay1 formulae and intraoperative
ORA measurements with respect to accuracy of predicting residual
refractive error after cataract surgery in eyes with short axial length.
More eyes are needed in order to increase the power of the current
study.
Commercial Relationships: Shruti Sudhakar, None; Darren Hill,
None; Christopher Hill, None; Ingrid U. Scott, None; Brett Ernst,
None; Seth Pantanelli, Alcon (R)
Effect of Applanation Tonometry on Keratometry Measurements
Obtained with IOLMaster and Galilei Dual-Scheimpflug
Analyzer
Deepak Sambhara1, Christopher Hill1, Lisa Hart1, Jufu Chen2,
Ingrid U. Scott1, Seth Pantanelli1. 1Penn State Hershey Eye Center,
Penn State Hershey Medical Center, Hershey, PA; 2Influenza
Division, Centers for Disease Control and Prevention, Atlanta, GA.
Purpose: Accurate keratometry measurements are essential to
determine the optimal intraocular lens (IOL) power for implantation
during cataract surgery. Tonometry is performed routinely in the
preoperative work-up of cataract patients. The purpose of this study is
to investigate the effect of tonometry on keratometry measurements.
Methods: Keratometry measurements were performed on 36 eyes
from 21 patients with IOLMaster® 5 (Carl Zeiss Meditec) and Galilei
G4 dual-Scheimpflug analyzer® (Ziemer Group) immediately before
and after applanation tonometry with Tono-Pen XL® (Reichert
Technologies). Kflat, Ksteep power, and Ksteep axis values were
obtained with IOLMaster, and SimK flat, SimK steep power, and
SimK steep axis values were obtained with Galilei dual-Scheimpflug
analyzer®; measurements obtained before and after applanation
tonometry were compared using paired t-test analyses. A difference
of 0.25 diopters (D) or more between pre- and post-applanation is
considered clinically meaningful. A p-value < 0.05 is considered
statistically significant.
Results: The difference between pre- and post-applanation Ksteep
was 0.17 D (p=0.0125). The difference between pre- and postapplanation SimK steep measured by G4 was 0.07 D (p=0.0063).
The mean difference in spherical equivalent (SE) pre- versus postapplanation was 0.066 D (p=0.108) when IOLMaster was used,
and 0.064 D (p=0.0021) when G4 was used. No other statistically
significant differences, and no clinically meaningful differences, were
observed with regards to changes in the axes or the flat meridian
power measurements before versus after applanation tonometry.
Conclusions: Applanation tonometry with Tono-Pen XL® (Reichert
Technologies) is not associated with a clinically meaningful change
in keratometry measurements or SE obtained with IOLMaster and
Galilei dual-Scheimpflug analyzer.
Commercial Relationships: Deepak Sambhara, None;
Christopher Hill, None; Lisa Hart, None; Jufu Chen, None;
Ingrid U. Scott; Seth Pantanelli, Alcon (R)
Biometric factors associated with effective lens position in
capsular bag after cataract surgery
Julien PLAT, Arnaud Payerols, Max Villain, Didier Hoa,
Vincent Daien. CHU MONTPELLIER, MONTPELLIER, France.
Purpose: Effective lens position (ELP) in the capsular bag is one
of the main factor of refractive outcome after cataract surgery, as
suggested by Olsen and al. The aim of this study is to investigate the
clinical and biometrical factors associated with ELP depends of the
type of intraocular lens (IOL) we use.
Methods: This is a single-center prospective study conducted in the
public hospital of Montpellier between 2012 and 2015, from patients
who underwent uncomplicated standard phacoemulsification. We
collected clinical factors (age, sex, history, refraction, keratometry,
vitreous status) and biometrical factors (axial length, pachymetry,
anterior chamber depth, lens thickness, white to white) which may
affect ELP. Optical biometry was performed preoperatively and one
month postoperatively. Power and type of IOL were collected to
stratify patients into 3 groups: SN60WF Alcon®, ZCB00 Tecnis®,
Asphina409MV Zeiss®. ELP was measured by the c constant as
described by Olsen et al.
Results: 244 eyes from 181 patients were included (mean age 73.1
± 9.3 years). The c constant was respectively 0.38 ± 0.04, 0.44 ±
0.05, 0.39 ± 0.06 for the 3 groups SN60WF, ZCB00, ASPHINA. The
anterior chamber depth and anterior segment depth were two factors
significantly correlated with ELP (r = -0.44, p <0.0001; r = -0.31, p
<0.0001, respectively). The lens thickness was positively correlated
with ELP for ASPHINA IOL only (r = 0.52, p = 0.006). The age, sex,
refraction, keratometry, white to white, axial length, vitreous status
showed no significant correlation with ELP.
Conclusions: Estimating ELP by current formulas is probably one
main source of postoperative refractive error. The current formulas
such as SRK/T estimate ELP from keratometry and axial length,
without taking into account the anterior segment anatomy. However,
anterior segment anatomy is not always correlated to the axial
length in particular with extreme myopic and hyperopic eyes. The
latest generation of formulas, such as Olsen and Barrett formulas,
take more parameters into account to better estimate the ELP. This
study found that the ELP is correlated to anterior chamber depth and
anterior segment depth. The integration of these data in formulas may
improve the refractive outcome after cataract surgery.
Commercial Relationships: Julien PLAT; Arnaud Payerols, None;
Max Villain, None; Didier Hoa, None; Vincent Daien, None
After the Deed is Done: Viability and Applications of Anterior
Chamber Depth Measurements in Pseudophakes
Elizabeth Cotton, Ahmad Al-Heeti, Samir I. Sayegh. The EYE Center,
Champaign, IL.
Purpose: To assess the state of the art and potential application
of anterior chamber depth (ACD)/effective lens position (ELP)
measurements in pseudophakes.
Methods: In this study we proceeded to do three things: 1) Review
the literature for identifying the devices capable of measuring ACD
in pseudophakes 2) Compare in a small study involving six patients
ultrasound versus optical methods. 3) Develop matrix methods to
take advantage of ACD measurement to improve results on second
eye cataract surgery.
Results: In our study it was demonstrated that contact ultrasound
is more repeatable than optical methods used in IOLMaster 500,
though neither had the repeatibility required for reliable computation
associated with second eye surgery planning. While IOLMaster
does not recommend the use of the device to measure ACD in
pseudophakes, it does provide a specific setting to do so. There is a
reasonable agreement in the literature that for reliable measurements
ultrasound and possibly other devices that are much less commonly
accessible may be preferable to IOLMaster. Finally the matrix
method was developed and demonstrated to use measured ACD,
provided measurements within 0.1 mm can be obtained, to improve
outcomes on a second eye to be operated of a cataract surgery,
especially in circumstances where the patient needs to undergo
surgery prior to the stabilization of the refraction in the first eye, due
to postoperative anisometropia or other reasons.
Conclusions: ACD/ELP measurement in pseudophakes can be
very valuable and used as a specific tool for improving second eye
cataract surgery. Its measurement in most circumstances today is
best performed using ultrasound though novel optical technologies,
despite limitations, are constantly improving.
Commercial Relationships: Elizabeth Cotton, None; Ahmad AlHeeti, None; Samir I. Sayegh, None
Toric IOL Calculations for Refractive Cataract Surgery:
The Good, The Bad, and The Distorted
Samir I. Sayegh. Ophthalmology, Eye Center/The Retina Center,
Champaign, IL.
Purpose: With the rising success of toric intraocular (tIOL) lenses
to correct astigmatism at the time of cataract surgery, the repertoire
and range of such lenses have been rapidly expanding and associated
calculators, specific to a manufacturer or more broadly defined,
have proliferated. The purpose of this presentation is to examine the
underlying algorithms and methods used, properly or improperly, by
a variety of calculators. Good methodologies emerge but also some
serious limitations and these are classified as good, bad or distorted.
Methods: The consideration of tIOL calculators were evaluated on
the following criteria
1) Stand-alone-toric or allowing for sphere computation
2) Sequential computation of sphere then toric components or
allowing for simultaneous optimization
3) Appropriate addition/combination of corneal astigmatism and
surgically induced astigmatism
4) Allowing for additional astigmatism combination such as that
created by second incision or limbal relaxing incision (LRI)
5) Use of fixed toricity ratio, variable toricity ratio or combination
6) Allowing for meridional methods and its propoer implementation
7) Appropriate interface with flexibility for re-computation and
comparison
8) Ease of use of the graphical user interface (GUI)
Results: From the methods of computations examined, the majority
of calculation environments were found to be stand-alone-toric
implementing one portion of a necessarily sequential algorithm. The
methods of combining astigmatism were generally appropriate but
lacking generality, placing the burden of additional computations on
the user. Some did not display cross cylinder necessitating indirect
methods to elucidate results. Fixed toricity ratio methods were still
broadly used despite a growing awareness of their inappropriateness.
The meridional methods can be inappropriately applied, resulting
in distorted results. Flexibility for re-computation and comparison
was limited with few exceptions. There was a significant variability
in user experience and quality/functionality of GUI, including the
generation of a specific clear easy to use surgical plan.
Conclusions: While the use of tIOLs is growing rapidly with an
increasing range and repertoire of options for the patients, calculation
environments have continued to lag. A diagnostic approach and
systematic classification of significant flaws is proposed along with
suggested methods to address the shortcomings.
Commercial Relationships: Samir I. Sayegh
Stability and Variability of Calculators for FDA approved Toric
Intraocular Lenses (tIOLs)
Fatma Dihowm1, 2, Samir I. Sayegh2. 1Prince George’s Hospital
Center, Cheverly, MD; 2The EYE Center, Champaign, IL.
Purpose: To assess the stability of IOL online calculators for FDA
approved tIOLs through and during the second decade of the twenty
first century and propose a universal tool to address their limitations.
Methods: In this comparative study, the available software programs
for manufacturers of tIOLs were identified and used to calculate cross
cylinder, choice of one or more tIOL and corresponding residual
astigmatism for 45 standardized representative cases combining
different degrees and orientation of corneal and surgical induced
astigmatisms for IOL spherical equivalent (SE) and for spherical
powers ranging from 10 to 30 diopters. The results for each available
calculator, obtained in 2015, were compared to results for same
inputs as conducted in 2013. A subset of results available and
documented since 2011 were also compared with results for 2015.
Results: One of the online calculator was no longer available at the
time of the second testing. The other calculators remained relatively
stable with the exception of the introduction of newly approved
tIOLs extending the previous range. The limitations associated with
all calculators as pointed for example by (Goggin et al 2011) and
(Dihowm, Hjelmstad and Sayegh, Investigative Ophthalmology &
Visual Science April 2014, Vol.55, 3749; Dihowm, Jabra and Sayegh,
Investigative Ophthalmology & Visual Science June 2015, Vol.56,
1907) remained.
Conclusions: Online toric calculators from major IOLs
manufacturers remained relatively stable over a period of several
years. On the one hand this can help develop a significant intuition
and experience by surgeons using them in daily practice. However
as discrepancies and limitations remain unaddressed, a critical
review of tIOL calculators is needed. A possible tool to address these
limitations, the UniversIOL calculator, is proposed.
Commercial Relationships: Fatma Dihowm, None;
Samir I. Sayegh, None
Cross Cylinder Calculation Agreement Amongst toric IOL
Calculators and UniversIOL
Zhangying Chen1, Samir I. Sayegh2. 1University of Illinois at UrbanaChampaign, Champaign, IL; 2The Eye Center, Champaign, IL.
Purpose: As toric intraocular lenses (tIOLs) for the simultaneous
correction of astigmatism and refractive error in patients undergoing
cataract surgery become more sophisticated and more widespread, it
is crucial to determine the appropriate amount of astigmatism to be
corrected for the implantation of such lenses. The initial step of any
such algorithm is the addition of the preexisting corneal astigmatism
to the astigmatism induced by the incision(s) of the surgery, or
surgical induced astigmatism (SIA). Such a step, the analytical
aspects of which dates back to the 19th century, is made by all toric
calculators and made explicit by most, but not all. We propose to
verify that the results of such a calculation as performed by different
toric calculators for major manufacturers, as well as by a universal
calculator, are identical.
Methods: We compare the results of such calculations for seven
different calculators. Three calculators for tIOLs that are FDA
approved and three calculators for tIOLs available internationally but
not in the US. We finally compare results to a universal calculator,
UniversIOL, that provides power calculation for all intraocular
lenses, including toric lenses.
A standardized power set of 6 values of corneal astigmatism each at
6 different angles, combined with 6 values of SIA, also at 6 different
angles were combined to yield the “crossed astigmatism” for each
one of 6 commercially available calculators (5 online and one in an
app). The results were tabulated then compared to results obtained by
UniversIOL.
Results: All 6 calculators yielded nearly identical results for the
cross cylinder and agreed with results from UniversIOL. The only
difference was that for some cases one calculator differed by one
degree and that UniversIOL provided one additional significant digit
which may or may not be useful surgically.
Conclusions: There is general agreement in the results for cross
cylinder amongst multiple calculators (and UniversIOL provides
higher precision). This is important since all computations of
an appropriate tIOL involve this crucial step. The reason for the
discrepancies observed in residual astigmatism for the same eye
implanted with equivalent tIOL from different manufacturers
(F Dihowm and S Sayegh, ARVO 2014, AAO 2014) must originate at
a different step of the computation (Gabra and Sayegh, ARVO 2014).
Commercial Relationships: Zhangying Chen; Samir I. Sayegh,
None
Preliminary Analysis of an FDA-approved Variable Toricity
Ratio Toric IOL Calculator
Lauren Gabra1, 2, Samir I. Sayegh1. 1Ophthalmology, The Eye Center,
Urbana, IL; 2University Of Illinois at Urbana Champaign, Urbana, IL.
Purpose: To demonstrate the unrestrained combinations of values
allowed by an FDA-approved variable toricity ratio toric intraocular
lens (tIOL) calculator and the variability of toricity ratio for different
input combinations.
Methods: The tIOLcalculator under study was observed to accept
for input, in addition to K values, both the IOL power and the axial
length. Some such combinations correspond to emmetropia or near
emmetropia, which is the general pattern of use of most surgeons for
most patients worldwide. Other combinations however corresponded
to extreme myopic or hyperopic refractive targets of myopia or
hyperopia, with no corresponding warning generated. The toricity
ratio that can be computed acccording to the methods we developed
generated a matrix for each desired refractive target. We chose to
compute it for some unusual, yet “reasonable” refractive targets.
Using the UniversIOL Calculator (and confirming results with
IOLMaster and DGH6000 calculators), expected spherical equivalent
target values of -2, -5, and -8 were entered for specific high, average,
and low axial length values with high, average, and low mean corneal
power values to generate three 3x3 matrices of paired values, one for
each refractive target. The sphere power thus generated was entered
in the manufacturer’s toric calculator and a toricity ratio generated
for each axial length and mean corneal power pair at each expected
spherical equivalent target.
Results: The toric calculator accepted every pair of values and
suggested a toric lens, regardless of the expected spherical equivalent
targets being unusual or extreme. The toricity ratio for each matrix
was slightly different but generally followed the now recognized
trend of monotonic increase with both axial length and mean corneal
curvature.
Conclusions: The FDA-approved calculator under study allowed for
axial length and mean corneal power pairs resulting in unrealistic/
generally undesirable surgical outcomes. For each given refractive
target, its general trend for toricity ratio correlated with recognized
trends. Variability for different refractive targets is under active
investigation. Identifying the limitations of the method may lead to
better surgical outcomes.
Commercial Relationships: Lauren Gabra, None; Samir I. Sayegh
Astigmatism Correction in Laser Cataract Surgery. Comparison
of IOL Master and Corneal Topography measurements, how
Accurately do these Devices Account for the Role of Posterior
Corneal Astigmatism?
Mario J. Rojas1, 2, Debora Garcia-Zalisnak1, Peyton Neatrour2, 1.
1
Ophthalmology, EVMS, Norfolk, VA; 2Ophthalmology, Beach Eye
Care, Virginia Beach, VA.
Purpose: To compare PreOperative IOL Master(IOLm) and Corneal
Topography(CT) Ks and PostOperative(PO) results. We also seek to
understand some of the factors resulting in outcomes not predicted
preoperatively, at the time of toric IOL selection.
Methods: Retrospective review of 50 Toric IOL eyes, comparing
IOLm vs CT values. All patients underwent cataract extraction
with LenSx laser assisted surgery and received a 20 degree laser
astigmatism correction, performed at the steepest meridian.
PO goal was defined as: +/- 0.50D and < 10 degrees of axis. Failure
was defined as: cylinder >0.50D, and/or off axis >10 degrees.
Failure were also categorized as Under-Correction (UC) or OverCorrection(OC). Factors assessed included: type of Astigmatism(Ast)
corrected, High Ast >2.5D, intraoperative aberrometry (ORA)
measured with LenSx and Posterior Ast(PA) measured with
Pentacam.
Results: When comparing IOLm vs CT: cylinder differed by > 0.50D
in 36% of cases, and axis differed by > 10 degrees in 32% of cases.
58% of cases reached PO goal of cylinder < 0.50D and axis < 10
degrees. 16% of the cases where found to be UC, with 88% having
preoperative ATR Ast. 26% of the cases where OC, with 86% having
preoperative WTR Ast. High Ast accounted for 25% of UC, and
29% of OC. ORA underestimated 25% of the UC cases, and ORA
suggested and insufficient decrease in 14% of OC. PA accounted for
88% of UC, and 86% of OC, resulting in the most influential factor
for improving IOL selection.
Conclusions: IOLm uses partial coherence interferometry, where
as CT uses placido-based technology, both measurement devices
do not factor in PA. Pentacam uses scheimpflug technology and has
been found to accurately assess anterior and posterior corneal Ast.
This study shows that the influence of PA, most commonly resulted
in less than optimal toric IOL selection. Our results also demontrate
UC of ATR Ast, along with OC of WTR Ast. Our data supports the
concept of factoring PA into toric IOL selection. These findings have
been described in the literature and have become well accepted. Koch
et al., proposed a nomogram, and suggested that 0.5 D should be
subtracted in WTR Ast and 0.3 D should be added for ATR Ast. More
studies are needed to solidify these ideas, and compare the accuracy
of measuring PA with different devices.
Commercial Relationships: Mario J. Rojas;
Debora Garcia-Zalisnak, None; Peyton Neatrour, None
Validity of prediction models used to determine post-operative
corneal shape following cataract surgery
Phillip J. Buckhurst1, Catriona Hamer1, Hetal Buckhurst1,
Christine Purslow2, Nabil Habib3. 1Plymouth University, Plymouth,
United Kingdom; 2Cardiff University, Cardiff, United Kingdom;
3
Derriford Hospital, Plymouth, United Kingdom.
Purpose: Toric calculators predict the post-operative corneal shape
based on the pre-operative corneal power and the surgeon specific
surgically induced astigmatism (SIA). If the corneal incision is placed
oblique to the steepest corneal meridian then a toric calculator will
predict that the orientation of the post-operative corneal steepest
meridian will move away from the incision site. We conducted a
prospective clinical study to examine the actual effect of corneal
incisions when placed oblique to the steepest meridian.
Methods: 145 subjects (74.8±9.6 years) underwent cataract surgery
with a clear corneal incision placed oblique to the steepest corneal
meridian. Scheimpflug tomography was used to determine the
corneal power pre-operatively and post-operatively (3-6 months).
The preoperative measurements and surgeon specific SIA were
used to calculate the predicted post-operative corneal power. Two
models were created to examine the correction that would have been
achieved had a toric intraocular lens (IOL) been implanted. The
first model used the toric calculator predicted corneal astigmatism
(predicted) and the second used the pre-operative corneal data alone
(actual)
Results: The predicted median shift in the steepest corneal meridian
was 11.2° (IQR 6.0, 20.5°) away from the incision site. The median
actual change was only 2.9° (IQR -6.5, 13.7°). Toric calculators
significantly overestimate the overall change in axis for this cohort
(p<0.001), and a poor correlation was found between the predicted
and actual corneal axis change (r=0.086, p=0.14). The two models
showed significantly different residual ocular astigmatic values
(P<0.001) with the predicted (0.64D) being higher than the actual
(0.40D) model
Conclusions: The oblique cross cylinder formulae used in the
toric IOL calculators overestimates the shift in orientation of the
steepest corneal meridian following cataract surgery. The findings
would suggest that when using an corneal incision oblique to the
steepest meridian that the toric IOL should be selected and placed in
accordance with the pre-operative corneal power alone and not the
corneal power as predicted through vector analysis
Commercial Relationships: Phillip J. Buckhurst,
None; Catriona Hamer, None; Hetal Buckhurst, None;
Christine Purslow, None; Nabil Habib, None
Cataract lens model and measurement of the lens fragmentation
quality
Alexander Vankov, Phillip Gooding, Georg Schuele. AMO Sunnyvale,
Abbott Medical Optics Inc., Sunnyvale, CA.
Purpose: Optimization of the laser parameters suffers from the
lack of a reliable cataract model to assess the cut quality. Here we
present a porcine lens based cataract model for the optimization of
femtosecond laser fragmentation.
Methods: Artificial aging of the porcine lens was achieved by
storing fresh porcine lenses in a mixture of 50% alcohol and 50%
paraformaldehyde fixative solution for different durations followed
by storing for 24 hours in phosphate buffered saline (1x). Grade 1
cataract was achieved following 2.5 hours of submersion in solution;
3 hours and 4 hours in solution resulted in 2 and 3 grades of cataract,
respectively.
The lenses were irradiated using the CATALYS ® System and
fragmentation patterns were applied. Standard settings of 10um
horizontal and 40um vertical spot spacing were used.
After exposure, treated lenses were examined under the surgical
microscope. We evaluated the percentage of remaining tissue bridges;
the variation of depth as well as phaco emulsification was performed.
Results: We found that cataractous lens can be successfully
simulated and cut with the CATALYS ® System (Fig.1). The depth of
the cut increases with the increase in laser energy, See Fig.2. Phaco
emulsification can be performed with ultrasonic energy similar to that
found in standard clinical settings.
Conclusions: We introduced and evaluated a novel cataract model
for laser-assisted cataract surgery. Based on this model, one can
achieve a good full depth fragmentation starting at 5uJ of energy.
© 2015 Abbott Medical Optics Inc.
Fig.1 Cross section of the pig lens with laser pattern. Catalys®
System, 8uJ
Figure 2: Percentage of lens depth cut as function of laser energy.
Commercial Relationships: Alexander Vankov, Abbott Medical
Optics, Abbott Medical Optics (P); Phillip Gooding, Abbott Medical
Optics, Abbott Medical Optics (P); Georg Schuele, Abbott Medical
Optics (P), Abbott Medical Optics
Depth of focus measurements of ophthalmic surgical microscopes
Jim Schwiegerling1, Ramon C. Dimalanta2. 1Optical Sciences,
University of Arizona, Tucson, AZ; 2Alcon Research, Lake Forest,
CA.
Purpose: The purpose of this study is to develop an objective and
reliable means for measuring the perceived depth of focus for surgical
microscopes.
Methods: The depth of focus (DOF) for a series of ophthalmic
surgical microscopes (Alcon LuxOR with 175 mm and 200 mm
working distances (WDs); Zeiss 700 and OPMI with and without
DOF enhancement; Leica M820 with and without DOF enhancement)
was assessed. A target with a calibrated ruling pattern on its surface,
is angled at 45° to the surgical microscope objective. Images of the
target are captured through the microscope’s objective lens and ocular
and processed to extract DOF information. A profile through the
tick marks on the ruling in captured images was digitally analyzed
to quantify DOF. The local sharpness is calculated as the Full Width
Half Maximum (FWHM) dimension of each tick. A threshold
width of 20 pixels was chosen to define the boundaries of the DOF.
The range of sharp tick marks below this threshold was converted
to a physical distance using the known image magnification. The
measured DOF is compared across various microscope platforms and
accounts for differences in lens design and illumination.
Results: The LuxOR with a 200 mm WD had DOFs of 6.58 and 3.96
mm, for the 7X and 10X magnifications, respectively. Reducing the
WD to 175 mm changed the LuxOR DOFs to 5.87 and 3.73 mm. The
Leica 820 with depth enhancement on had DOFs of 5.98 and 2.46
mm. Switching off the depth enhancement modified the DOFs to 4.00
and 2.33 mm. The Zeiss OPMI with depth enhancement on had DOFs
of 5.98 and 2.46 mm. Switching off the depth enhancement modified
the DOFs to 3.81 and 2.40 mm. Finally, the Zeiss 700 had DOFs of
4.78 and 3.22 mm.
Conclusions: The DOF of surgical microscopes varies across design.
Theoretical descriptions of DOF rely solely on the numerical aperture
and magnification of the microscope. These measures do not account
for differences in lens design, aberrations and illumination. We
have developed an objective means of measuring DOF that captures
these additional effects. Based on our results, DOF is enhanced by
using collimated illumination in front of the objective lens. DOF
enhancement in some microscopes is also achieved through reducing
the pupil size which dims the overall image. It was determined that
the DOF was highest for the LuxOR microscope using its 200mm
objective at both 7X and 10X magnification amongst all systems
tested.
Commercial Relationships: Jim Schwiegerling, Alcon Research,
Ltd (F); Ramon C. Dimalanta, Alcon Research, Ltd
Support: Alcon Research Ltd.
Validation of the Rabbit Intracameral Inflammatory Assay as a
Lot Release Test for Ophthalmic Viscosurgical Devices
Lisa Walker, Rebecca Rice, Wendy Martin, Keven Williams,
Chris Steele, Suzette Craig, Sally Buck. Alcon, Fort Worth, TX.
Purpose: Due to the biologically derived nature of Ophthalmic
Viscosurgical Devices (OVDs), a reliable and reproducible assay
is essential to detect potential inflammatory contaminants. These
preclinical studies validate a rabbit intracameral inflammatory assay
for OVDs to predict their inflammatory potential as discussed in FDA
Guidance document Endotoxin Testing Recommendations for SingleUse Intraocular Ophthalmic Device issued August 17, 2015.
Methods: Forty-five male rabbits were randomized into 3 replicate
studies containing 3 groups of 5 animals each. Each rabbit received
a single 100µl intracameral injection into the right eye of Balanced
Salt Solution (BSS), a control OVD lot or an OVD lot spiked with
~ 1 EU/ml of endotoxin. A different lot of OVD was utilized for
each replicate. Rabbits were examined for the following pivotal
inflammatory criteria via slit lamp at approximately 8 and 24 hours
post-injection: conjunctival congestion, anterior chamber white
blood cells (WBCs), aqueous flare, aqueous fibrin, and iritis. Flare
and WBCs were graded according to the SUN scale while remaining
criteria were graded utilizing the Hackett-McDonald Ocular
Scoring System. Pilot studies were conducted to determine optimal
observation times, procedure-related background inflammation, and
threshold inflammatory criteria for each parameter in this model.
Results: Based on pilot study data, the following criteria were set for
each of the pivotal parameters: Anterior Chamber WBCs, x ≤ 1.5;
Aqueous flare, x ≤ 1.5; Iritis, x ≤ 1.0; Fibrin, x ≤ 1.0; Conjunctival
Congestion, x ≤ 2.0, where x indicates the mean score of 5 eyes.
Exceeding the criteria for one or more of the parameters at 8 or 24
hours resulted in lot failure. Furthermore, if any individual animal’s
WBC score was 4 at 8 or 24 hours, or if any 2 individual animal’s
WBC score was ≥ 3 at 8 or 24 hours, the lot would fail regardless of
the mean score. During the pivotal evaluation, three replicate studies
demonstrated that three individual lots of OVD spiked with ~ 1.0 EU/
ml endotoxin exceeded at least one of the acceptance criteria for the
assay while BSS and three individual lots of control OVD met all of
the acceptance criteria.
Conclusions: Based on the criteria set in the pilot studies, the
pivotal studies were successfully completed, validating the Rabbit
Intracameral Release Assay using endotoxin as a positive control.
Commercial Relationships: Lisa Walker, Alcon; Rebecca Rice,
Alcon; Wendy Martin, Alcon; Keven Williams, Alcon;
Chris Steele, Alcon; Suzette Craig, Alcon; Sally Buck, Alcon
A NEW SURGICAL TECHNIQUE IN CONGENITAL
CATARACT WITH FEMTOSECOND LASER
PAOLO BORDIN, GABRIELE VIZZARI. Ophthalmology, Hospital of
legnago, Legnago, Italy.
Purpose: The aim of this study is to describe a technique for
performing cataract surgery with a femtosecond laser (FLACS) in
infants with bilateral polar cataract, by using a viscoelastic substance
to visualize the posterior capsule.
Methods: A 2-year-old male presented with bilateral polar cataract
visualized on slitlamp examination. His best-corrected visual acuity
(BCVA) was 20/200 in OD and 20/100 in OS. The keratometry
(SRK-Tformula) is obtained with IOL Master and the axial length
with Ultrasound biomicroscopy. He underwent bilateral FLACS
(Victus, B&L) followed by implantation of a intraocular lens
(IOL). Anterior capsulotomy of 5 mm is performed by the laser.
The eye has been opened for lens aspiration without complications.
A capsular tension ring is implanted in the bag using a cohesive
viscoelastic substance to avoid the future phimosis. A hole is created
in the posterior capsule using a 27G needle and filled a short-chains
viscoelastic device through the gap in the vitreal chamber, between
the posterior capsula and the hyaloid. A new docking of the laser is
performed after the closure of the corneal wounds. The real timeintegrated optical coherence tomography (OCT) also visualizes the
posterior capsule pushed up by the viscoelastic, allowing a centered
central posterior capsulotomy of 4.5 mm, followed by mechanical
anterior vitrectomy. A IOL is implanted in the bag of both eyes.
Results: The child was followed up on day 1, day 5, at 2 weeks,
4 weeks and 8 weeks. At each follow-up visit, complete ocular
examinations including orthoptic examination of both eyes were
performed. The cornea was clear and the intraocular pressure(IOP)
was 15mmHg in OU at every visit. At 4 weeks the BCVA was
20/30 in OU.Anterior and posterior capsulotomies were complete
and uniform, without tears. The IOL was centered in the bag. No
complications were encountered.
Conclusions: The technique has been performed in a infant with
congenital cataract and it can enhance the quality of pediatric cataract
surgery. The capsule is very elastic and tends to tear peripherally in
manual anterior capsulotomy. This can induce to a complete loss of
the capsule protection during surgery, with damage of the capsular
scaffold for the IOL placement. Using the viscoelastic to push up the
capsule allow a better visualization of the capsular surface, in order
to standardize the laser capsulotomy procedure and to obtain a safe,
precise and repetitive surgery.
Commercial Relationships: PAOLO BORDIN, None;
GABRIELE VIZZARI
Tissue Plasminogen Activator for the Treatment of Fibrin After
Lensectomy with Intraocular Lens Insertion in a Juvenile Rabbit
Model
Joseph Bogaard1, Jonathon Young3, Iris S. Kassem2. 1Ophthalmology
and Visual Sciences, University of Illinois at Chicago, Chicago, IL;
2
Ophthalmology and Visual Sciences, Medical College of Wisconsin,
Milwaukee, WI; 3Cell Biology, Neurobiology & Anatomy, Medical
College of Wisconsin, Milwaukee, WI.
Purpose: To determine if tissue plasminogen activator (tPA) can treat
postoperative fibrosis and improve the clarity of the visual axis after
lensectomy with intraocular lens (IOL) insertion in a juvenile rabbit
animal model.
Methods: All experiments were approved and in compliance with
Animal Care Committee at the University of Illinois at Chicago and
the Medical College of Wisconsin. 9 juvenile (6-7 week old) New
Zealand White rabbits had unilateral lensectomy with intraocular
lens insertion under general anesthesia. Clear-cornea lens extraction
surgery was performed followed by insertion of an acrylic fIOL
(Alcon SN60WF 30D). Topical antibiotic ointment was given for 3
days postoperatively.
Rabbits were examined under sedation postoperatively on days
3 through 7 and on day 14 with slit lamp biomicroscopy and
optical coherence tomography (OCT) (Spectralis OCT, Heidelberg
Engineering). Anterior chamber inflammation was quantified using
the SUN classification system. OCT signal strength was used
as a quantification of the clarity of the central visual axis. After
examination on day 3, eyes were injected with 25 micrograms of
recombinant rabbit tPA (Molecular Innovations) (n=5) or balanced
salt solution (control) (n=4) into the anterior chamber.
Results: Lensectomy with IOL insertion resulted in a fibrin clot and
inflammation of the anterior chamber similar to previous reports
(1). Compared to controls, tPA injected on day 3 after lensectomy
reduced fibrin in the anterior chamber from 64% to 15% (p<0.001)
and improved OCT signal strength from 2.88 to 14.4 (p<0.001) 1
day after treatment. Both measures continued to be improved for
the tPA treated group for the remainder of the examination period.
Inflammation of the anterior chamber was significantly greater in
eyes treated with tPA. There was no increase in the incidence of
intraocular bleeding in eyes treated with tPA.
1. Bogaard JD, Kassem IS. Evaluation of therapeutic interventions
for postoperative inflammation and fibrosis in a juvenile rabbit model
of lensectomy. Invest. Ophthalmol. Vis. Sci.. 2015; 56(7):3217.
Conclusions: tPA significantly reduces fibrin in the anterior chamber
after lensectomy and may be an alternative to surgical removal of
fibrin membranes after lensectomy.
Commercial Relationships: Joseph Bogaard, None;
Jonathon Young, None; Iris S. Kassem, None
Support: NEI K08 EY024645; NEI Core Grant P30 EY001792;
Knights Templar Eye Foundation; RPB Departmental Support
Pupillary dynamics of patients on tamsulosin exhibiting
intraoperative floppy iris syndrome (IFIS) during cataract
surgery
Poonam Misra, Bella Wolf, Chetra Yean, Anurag Shrivastava.
Ophthalmology, Montefiore Medical Center, New York, NY.
Purpose: Prior studies have indicated that pupillometry detects
altered pupillary dynamics in patients who are on tamsulosin. The
purpose of our prospective cohort study was to compare pre-surgical
pupillary dynamics in patients who have taken tamsulosin with
control patients scheduled for cataract surgery. We aimed to identify
differences in pupillary dynamics of those tamsulosin patients
who developed IFIS during surgery with those who did not. This
study will indicate if there is increased risk of IFIS in tamsulosin
patients detectable via the Neuroptics NPi-200, a handheld, digital
pupillometer.
Methods: This study included 11 eyes of 11 tamsulosin patients and
31 eyes of 31 control patients. Pupillary dynamics were measured
before and after dilation for patients who underwent cataract
surgery between July 2015 and August 2015. Resting pupil diameter
(mm), constricted pupil diameter (mm), constriction latency (ms),
constriction and dilation velocity (m/s) were measured. The surgeon,
masked to the groups, determined the presence of IFIS and rated
severity based on a literature based grading scale. Patients over
the age of 18 were included regardless of existing comorbidities.
Two-tailed t-tests were used to compare differences between the two
groups.
Results: Mean pre-dilated max diameter for tamsulosin patients
was 3.15±0.66, 16 percent smaller than mean for control patients
(3.73±0.93, p=0.03). Mean pre-dilated resting diameter for
tamsulosin patients was 2.27±0.37, 16 percent smaller than the mean
for controls patients (2.70±0.72, p=0.01). Other pupillary dynamics
were not significantly different between the two groups. Of the 11
tamsulosin patients, 45% (5) exhibited IFIS, ranging from grade 1
to grade 3. No significant differences of pupillary dynamics were
found between IFIS and non-IFIS Flomax patients. Mean post-dilated
max diameter approached significance, with IFIS patients being 17%
smaller (5.91±1.16) than non-IFIS (7.15±0.93, p=0.07).
Conclusions: Pupillometry measured significant differences in
pupillary dynamics between patients on tamsulosin and controls. It
also identified differences approaching significance between IFIS
patients and non-IFIS patients, specifically post-dilated maximum
pupil size. Pupillary dynamics of patients on tamsulosin may be
measured prior to surgery to determine if IFIS is likely to occur,
allowing special precautions.
Commercial Relationships: Poonam Misra, None; Bella Wolf,
None; Chetra Yean, None; Anurag Shrivastava
Cataract Surgery Training Curricula and Timing of Resident
Participation in Phacoemulsification Cataract Surgery
Ramunas Rolius, Seth Pantanelli, Ingrid U. Scott. Ophthalmology,
Penn State Milton S. Hershey Medical Center, Hershey, PA.
Purpose: To investigate cataract surgery training curricula and timing
of resident participation in phacoemulsification cataract surgery
(phaco) as primary surgeon.
Methods: An anonymous survey including multiple choice and
Likert-style questions was created on surveymonkey.com. An e-mail
with a description of the study and link to the survey was sent to the
program director (PD) of each ophthalmology residency training
program accredited by the Accreditation Council for Graduate
Medical Education (ACGME). Weekly reminders were sent for 2
consecutive weeks.
Results: Fifty of 116 (43%) PDs completed the survey. Over 2/3
(72%) of PDs indicated their program had a formal cataract surgery
training curriculum which most commonly included lectures (88%)
and wet lab (91%). Most PDs reported their residents begin learning
phaco using clear corneal incision (91%) and divide and conquer
(100%). The proportion of PDs who indicated their residents start
performing phaco as primary surgeon in the first, second, or third
year of residency was 34%, 56%, and 10%, respectively. Only 1
(2%) PD reported a requirement to perform extracapsular cataract
extraction (ECCE) before attempting phaco. Inadequate resident
knowledge and surgical skill base (58%), anticipation of increased
surgical complication rates (38%), and no perceived benefit to
resident education (32%) were the most commonly reported barriers
for implementation of earlier resident performed phaco. The
proportion of PDs who believed that surgical complication rates
of resident performed phaco would be higher if residents started
performing phaco as primary surgeon in the first or second year
instead of the third year of residency was 38% and 8%, respectively.
Conclusions: Survey results indicate that while most training
programs have a formal cataract surgery training curriculum, over
25% of ACGME-accredited programs do not. Residents begin
performing phaco as primary surgeon in the first 2 years of residency
at the majority of training programs in the United States, and
residents are no longer required to complete a certain number of
ECCE surgeries before attempting phaco. Program directors perceive
inadequate resident knowledge and surgical skill base, as well as
anticipation of increased surgical complication rates, as barriers to
early resident exposure to phaco as primary surgeon.
Commercial Relationships: Ramunas Rolius, None;
Seth Pantanelli, None; Ingrid U. Scott, None
Implementation of a Model Eye (Kitaro) Based Cataract Surgery
Training Curriculum
Carrie Wright1, Ingrid U. Scott1, Christine Callahan1,
George C. Papachristou1, Yousuf Khalifa2, Seth Pantanelli1.
1
Ophthalmology, Penn State Milton S. Hershey Medical Center,
Hershey, PA; 2Ophthalmology, Emory Eye Center, Atlanta, GA.
Purpose: The Accreditation Council for Graduate Medical Education
(ACGME)’s requirements for ophthalmology residency training
programs specify that a surgical skills development resource be
available to residents. A wet lab course was developed that blends
formal didactic teaching with hands-on surgical training and timely
individualized feedback on developing surgical skills, incorporating
the Kitaro DryLab and WetLab kits.
Methods: A six-week course was developed for PGY-2 and PGY3 ophthalmology residents. Each week began with a one-hour
didactic session on selected critical steps of phacoemulsification
cataract surgery and related practical perioperative and intraoperative
considerations. Residents were subsequently accompanied by faculty
to the wet lab for demonstration of the same critical steps on the
Kitaro DryLab/WetLab kit. Residents were then required to practice
and submit video of their performance of the specified technique for
faculty evaluation. Faculty reviewed the video off-line for objective
assessment of specific required surgical competencies and provided
individualized written and verbal feedback on resident performance.
Results: Video submissions from completed assignments
demonstrated that the residents were able to practice, in a wet lab
setting, wound construction, capsulorhexis, nucleus disassembly,
cortical cleanup, and intraocular lens insertion in a way that closely
resembled operating room experience.
Conclusions: This is the first study to describe a cataract surgery
training curriculum based on the Kitaro DryLab and WetLab
cataract surgery training kits. The Kitaro training kit provided an
accurate, true-to-life model on which to practice the critical steps of
phacoemulsification cataract surgery. Additional studies are needed
to further evaluate whether implementation of this curriculum affects
outcomes and efficiency in the operating room. Cataract surgery
procedure times, vision-threatening complications, and non-visionthreatening complications data are currently being collected on
surgical cases performed by residents trained using this curriculum,
with outcomes analyses to follow after sufficient data have been
amassed for comparison with data collected on surgical cases
performed by residents trained prior to implementation of the new
curriculum.
Commercial Relationships: Carrie Wright, None; Ingrid U. Scott;
Christine Callahan, None; George C. Papachristou, None;
Yousuf Khalifa, None; Seth Pantanelli, Alcon (R)
Surgical outcomes following complicated phacoemulsification
cataract surgery performed by beginner resident surgeons
Kevin Miller, Raouf Sherief, Kevin Kaplowitz, Timothy Chou,
Azin Abazari. Ophthalmology, SUNY Stony Brook, Smithtown, NY.
Purpose: The rate of intraoperative complications in beginner
cataract surgeons during ophthalmology residency has been shown
to be significantly higher compared to their more experienced
counterparts. A “learning curve” of resident training for
phacoemulsification has been previously described. The aim of
this retrospective study is to investigate the final visual outcome
in patients with complicated cataract surgery. This study will
evaluate if our patients still had good visual outcomes despite these
intraoperative complications.
Methods: After obtaining institution review board approval, a
retrospective chart review of all cataract surgeries done by second
year residents at our institution was performed. Surgeries done by 8
consecutive second year residents from 2010 to 2015 were analyzed
for this study. Patients with an intraoperative complication, including
posterior capsule tear, vitreous loss, dropped lens fragment, or any
other non-routine event were included for analysis in this study.
Results: Of 150 cataract surgeries performed by beginner resident
surgeons, 24 cases with intraoperative complication were identified
(16%). Of these cases, 17 (70%) had preoperative risk factors for
surgical complications, including poor dilation, mature cataract, poor
red reflex, and pseudoexfoliation. In addition, 62.5% (15/24) had
ocular comorbidities limiting final visual outcome including macular
degeneration, advanced glaucoma, diabetic macular edema, and
tractional macular detachment. 41.6% (10/24) had visual acuity of
20/40 or better at their last visit. Of the 14 patients that did not have
a visual acuity of 20/40 or better, 9 had preexisting ocular pathology
limiting visual potential, and if these patients were excluded, 66.7%
(10/15) had acuity of 20/40 or better. Patients gained on average 8
lines of vision compared to their preoperative acuity.
Conclusions: Preoperative risk factors for surgical complications
may lead to high surgical complication rates in surgeries performed
by beginner resident surgeons. In carefully selected cases, patients
can achieve good final visual acuity after cataract surgery by beginner
resident surgeons. The overall complication rate was higher in this
study compared to some prior studies. This may be due to the fact
that only outcomes of beginner resident surgeons were analyzed,
rather than more experienced residents as in most prior analyses.
Commercial Relationships: Kevin Miller, None; Raouf Sherief,
None; Kevin Kaplowitz; Timothy Chou, None; Azin Abazari,
None
Effectiveness of Ophthalmic Surgical Simulation Training vs.
Paper Based Manual Training on physiologic tremor and speed in
dominant and non-dominant hands
Yonwook J. Kim1, 2, Abhishek R. Payal1, 3, Luis A. Gonzalez1,
Mary K. Daly1, 2. 1Veterans Affairs Boston Healthcare System,
Jamaica Plains, MA; 2Department of Ophthalmology, Boston
University School of Medicine, Boston, MA; 3Department of
Ophthalmology, Harvard Medical School, Boston, MA.
Purpose: Ophthalmic surgeries are bimanual but currently there is
little data on targeted training for both dominant and non-dominant
hands. We hypothesized that EyeSi simulator training and paper
based manual training would improve speed, reduce tremor, and
decrease the performance gap between dominant and non-dominant
hands.
Methods: In this prospective crossover study, nineteen subjects
(18 medical students and one resident) completed training sessions of
simulator anti-tremor modules and paper based tremor spirography
with their dominant and non-dominant hands. Data on baseline
performance, a series of training tasks and an evaluation test at
the end of each session were recorded. We compared the overall
simulator scores, number of paper errors, average tremor value
(as calculated by the simulator), and time to complete baseline and
final tasks, using analysis of variance and nonparametric tests.
Results: In the paper module, subjects significantly decreased the
overall time in both dominant and non-dominant hands (P <.001)
from baseline to final tasks, while the number of errors did not
change. In the simulator module, participants achieved a higher score
(P<.001) in less time (P <.001) in both dominant and non-dominant
hands after training. The improvement in scores was comparable
(P=.79) between hands. The simulator tremor values did not differ
significantly at baseline or final tasks for both hands (P=.37 for
baseline, P=.83 for final). Before the training, non-dominant hands
took longer than dominant hands to complete tasks on both paper
(P=.003) and simulator (P=.04) modules. After the training, nondominant speed still lagged behind that of the the dominant hand on
the paper module (P=.005) but improved to the level of dominant
hands on the simulator (P=.07). Overall the participants found the
simulator helpful in improving the speed of their non-dominant hand.
Conclusions: Structured repetitive simulator training and paperbased training can improve speed in both dominant and non-dominant
hands, but does not appear to reduce tremor. Simulator training may
be helpful in decreasing the performance gap between dominant and
non-dominant hands.
Disclaimer: The opinions expressed are those of the authors and not
necessarily those of the Department of Veterans Affairs or the United
States Government.
Commercial Relationships: Yonwook J. Kim, None;
Abhishek R. Payal, None; Luis A. Gonzalez, None; Mary K. Daly,
None
Pop and Chop vs. Divide and Conquer: Zero and Low Energy
Nucleus Disassembly Technique for Teaching Beginner Surgeons
Debora Garcia-Zalisnak, Fredric Gross. Ophthalmology, Eastern
Virginia Medical School, NORFOLK, VA.
Purpose: In most ophthalmology residency programs, the Divide and
Conquer (D&C) technique is taught as the initial method of nuclear
disassembly because of its safety and reproducibility. Pop and Chop
(P&C) is a less known technique in which the nucleus is prolapsed or
tilted into the anterior chamber, manually chopped, and then removed
by phacoemulsification. The purpose of this study was to compare
surgical case times, changes in pachymetry, amount of energy, and
complications between these two techniques.
Methods: This was a prospective, randomized, single center, nonblinded study. All the patients undergoing non-complex cataract
surgery at the Hampton Veterans Affairs Medical Center between
July and October 2015 were included. The resident was the primary
surgeon and was assisted by the attending using the Alcon Centurion
system. The cases were randomly assigned to the P&C or the
D&C technique. Patients with cataracts complicated by trauma,
pseudoexfoliation, or prior ocular surgery were excluded from the
study.
Results: Demographics characteristics data for the two groups
were compared in a univariate analysis using Student’s t-test for
continuous variables and Chi-Square test for categorical variables.
The study sample consisted of n=81 subjects of whom 45 (55.56%)
were in the D&C group and 46 (44.44%) were in the P&C. There
was no statistical difference between the two methods in terms
of demographics variables. The results of the Wilcoxon analysis
indicate that the D&C method used more total fluid (p< 0.001) and
had a greater CDE(p< 0.001). The P&C method had a greater change
in pachymetry from baseline to POD-1(p=0.0018). There was no
statistically significant change in baseline to POM 1 pachymetry or
in the complication rate between both groups. Of note, there were 3
cataracts that were removed using 0 CDE and 7 more using <1 CDE.
All of these cataracts were disassembled using the P&C technique.
Conclusions: P&C is a safe and efficient method of nucleus
disassembly that can be taught to beginner surgeons as easily as
D&C. When comparing with D&C, P&C proved to be faster and
required less energy. P&C leads to more corneal edema acutely after
surgery but this edema was resolved in both groups at the end of the
first month. In otherwise healthy eyes with non-complex cataracts,
P&C proves to be a worthy tool to add to a beginner surgeon’s
technique arsenal.
Commercial Relationships: Debora Garcia-Zalisnak, None;
Fredric Gross, None
Visual and anatomic outcomes after intraoperative complications
in resident-performed phacoemulsification surgery
Marianeli Rodriguez1, 2, Ninel Gregori1, 2, Karli Sapir2,
Anna K. Junk1, 2, Anat Galor1, 2, Sarah Wellik1, 2, Raquel Goldhardt1, 2,
Jesse Pelletier2, Wei Shi1. 1Ophthalmology, Bascom Palmer Eye
Institute, Miami, FL; 2Department of Veterans Affairs, Miami, FL.
Purpose:
To review visual and anatomic outcomes after complicated cataract
surgery in a teaching institution.
Methods:
IRB approved non-comparative consecutive case series of
complicated phacoemulsification surgeries performed by
ophthalmology residents under direct supervision of the attendings
between January 1, 2006 and December 31, 2014.
Results:
133 eyes were analyzed. The mean final BCVA was 20/40.
BCVA improved by a mean of 8 letters at 1 month (N=128; p=0.001),
16 letters at 3 months (N=117; p<0.001), 14 letters at 6 months
(N=79; p<0.001), and 4 letters at 12 months (N=34; p=0.37). The
mean OCT central subfoveal thickness (CST) increased by 36 μm
(N=45; p<0.001), 27 μm (N=33; p=0.015), 45 μm (N=23; p=0.004),
and 7.7 μm (N=10; p=0.62) at 1, 3, 6, and 12 months. BCVA
increased by 3 lines in 41%, 56%, 57%, and 44% of eyes at 1, 3,
6, and 12 months. Sixty (45%) eyes required a secondary surgical
procedure. Normal fovea was present in 66%, 59%, 39%, 44%,
33% OCTs obtained at preoperative, 1, 3, 6, and 12 months visits.
Intraretinal fluid was present in 1.5%, 3.6%, 2.2%, and 9.5% eyes at
1, 3, 6, and 12 months. Visual acuity change did not correlated with
the macular thickening seen on the OCT at any time point.
Conclusions:
A high proportion of eyes with complicated cataract extraction
history requires additional surgical procedures however the visual
gains are substantial.
Commercial Relationships: Marianeli Rodriguez; Ninel Gregori,
Second Sight Medical Products, Inc. and Ocata Therapeutics,
Inc. (C); Karli Sapir, None; Anna K. Junk, None; Anat Galor,
Department of Veterans Affairs, Veterans Health Administration,
Office of Research and Development, Clinical Sciences Research
and Development’s Career Development Award CDA-2-024-10S
(Dr. Galor), NIH Center Core Grant P30EY014801 and Research
to Prevent Blindness Unrestricted Grant. (R); Sarah Wellik, None;
Raquel Goldhardt, None; Jesse Pelletier, None; Wei Shi, None
Support: NIH Center Core Grant P30EY014801, Research to
Prevent Blindness Unrestricted Grant, Department of Defense (DODGrant#W81XWH-09-1-0675).
Comparison of cumulative dissipated energy utilized in phaco
chop versus divide and conquer during phacoemulsification as
performed by a resident surgeon
Katie M. Keck, Michael Patterson, Bethany Markowitz.
Ophthalmology, Palmetto Health, Columbia, SC.
Purpose: The divide and conquer technique for cataract extraction
is the traditional technique that has been taught during residency
training. However, several other techniques for cataract extraction
have been developed and include the phaco chop technique, which
eliminates sculpting of the cataractous lens performed in the
traditional technique of divide and conquer. This study tests the
hypothesis that the phaco chop technique can be an effective and
efficient technique to learn during residency training.
Methods: This is a retrospective review of 137 patients who
underwent cataract extraction by a single resident surgeon over a
one-year period. In 67 patients, the divide and conquer technique
was utilized, while the phaco chop technique was performed
in 70 patients. The cumulative dissipated energy (CDE), total
phacoemulsification time, and operative time were compared between
the two groups using the two-tailed student’s t-test for statistical
analysis.
Results: Cumulative dissipated energy was significantly lower in
the phaco chop group (mean 6.66 +/- 5.11[SD]) than in the divide
and conquer group (mean 12.71 +/- 5.94)(p < 0.001) as was total
phacoemulsification time (mean 27.30 sec +/- 20.63 in the phaco
chop group vs mean 45.42 sec +/- 18.81 in the divide and conquer
group [p <0.001]). Additionally, the operative time was significantly
shorter in the phaco chop group (mean 12.23 min +/- 5.25) than in the
divide and conquer group (mean 18.51 min +/- 7.18) (p< 0.001).
Conclusions: Our results indicate that the phaco chop technique
can be an effective and efficient technique to learn during
residency training. The phaco chop technique may require less
phacoemulsification energy than the divide and conquer technique,
leading to more efficient removal of the nucleus and thus allowing for
shorter operative times.
Commercial Relationships: Katie M. Keck, None;
Michael Patterson, None; Bethany Markowitz, None
Resident Surgeon Efficiency in Femtosecond Laser Assisted
Cataract Surgery
Brian R. Sullivan. Ophthalmology, Loyola University Medical
Center, Maywood, IL.
Purpose: The objective of the study is to compare procedural
efficiencies of resident performed femtosecond laser assisted cataract
surgery versus conventional phacoemulsification.
Methods: A retrospective chart review was conducted for
consecutive senior resident cases of phacoemulsification cataract
surgery performed under single attending supervision during a nine
month period. Medical records were reviewed to record demographic
information, operative procedure interval times, total OR room
interval times, and surgical complications. Operating room video
records for each case were reviewed to quantify interval times for
completion of five core steps of the procedures, including incision,
anterior capsulotomy, nucleus removal, cortical removal, and
intraocular lens implantation.
Results: Total room time, total operation time, and incision time
were all found to be significantly longer in the laser group versus
the traditional phaco group (each p < 0.05). The mean difference in
total operating time for the FLACS group was 8.6 minutes longer
than the traditional group (p < 0.001). Average total room time was
9.0 minutes longer in the FLACS groups (p = 0.02). By contrast,
the mean duration for manual completion of anterior capsulotomy
was significantly shorter in the femtosecond laser group compared
to traditional phacoemulsification (p < 0.001). There were no
statistically significant differences for the individual steps of nucleus
removal, cortical removal, or IOL insertion and placement. Rates
of surgical complications were not significantly different (p=0.22)
between the groups.
Conclusions: Early resident experience with femtosecond cataract
surgery is generally less efficient than traditional phacoemulsification
regarding total OR time, total procedural time, and incision time.
FLACS showed a small advantage in shorter mean time for manual
completion of capsulotomy, but subsequent surgical steps were not
shorter or longer. Resident learning curve for the FLACS technology
may partially explain the disparity of efficiency. The study did not
show a significant difference in operative complications between
FLACS and conventional surgery by the trainees. Educators should
be cognizant of a potential for lower procedural efficiency when
introducing FLACS into resident training.
Commercial Relationships: Brian R. Sullivan, None
Comparison of surgical and visual outcomes of
phacoemulsification performed by ophthalmology residents with
3 different machines
Karla O. VanDick-Sanchez1, Pablo J. Guzman-Salas1, 2,
Karla Y. Ruiz-Alvarez1, Eduardo Chavez-Mondragon1. 1Anterior
Segment, Instituto de Oftalmologia - Conde de Valenciana, Mexico
City, Mexico; 2Ophthalmology Professor, Universidad de Ciencias
Medicas, San Jose, Costa Rica.
Purpose: Compare surgical and visual outcomes of patients, treated
with phacoemulsification, in a reference center in Mexico City, by
ophthalmology residents, with different equipment
Methods: Retrospective, observational, randomized case series
study. Clinical data obtained from the Anterior Segment Department
Surgical Ophthalmology Resident Training Program at Instituto de
Oftalmologia-Conde de Valenciana in Mexico City, from June 1st
2014-June 1st 2015. Surgeries were performed under supervision of
the same attending physician, who decides what type of equipment
to use: Infiniti Vision System with Duovisc OVD and SN60WF lens;
Stellaris Vision Enhancement System with Amvisc Plus OVD and
MX60–enVista lens; and Faros with Hanita OVD1.8 and Focus 602
lens. Patients had minimum 6 month follow-up
Results: We analyzed 45 patients, in 3 groups. Total average age
71.07±8.11 years. Cataracts had average LOCS III NO of 2.3±0.63
and NC2.2±0.59; patients had best corrected visual acuity of
0.65±0.50logMAR, mean corneal keratometry 44.17±1.69D. Axial
length of 23.13±0.70 mm.
Groups were formed by machine used: Group1(Stellaris),
Group2(Faros), Group3(Infiniti). Average time of surgery was
66, 66.33 and 56.67 minutes respectively. Six, 7 and 3 patients
experienced complications, like posterior capsule rupture: 2 patients
in Group1 and 1 in Group2; Descemet membrane detachment:1,1
and 2 respectively. Zonular dialysis: 1, 2 and 1respectively. Two
patients in groups1 and 2 had an IOL placed on sulcus, the rest, in the
capsular bag. 24 hours postop BCVA: 0.56, 0.49 and 0.41logMAR.
Corneal edema in 12,15 and 9 patients respectively; leakage by the
main incision was reported in 2 patients in group1;anterior chamber
reaction for the 3 groups were 2+ anterior chamber cells.
BCVA in the final visit: 0.12, 0.14 and 0.12logMAR respectively.
Only 2 patients in group2 develop posterior capsule opacification.
Conclusions: All our patients were operated by 3rd-year
ophthalmology residents. We found more complications in group2,
followed closely by group1. However, final BCVA was the same in
group 1 and 3. The fewer complications and the better final BCVA
were achieved by group 3. However, results in the other groups are
similar.
We can conclude that in a certain type of cataracts, results by
ophthalmology resident cataract surgery are very similar. A bigger
study is necessary to have deeper conclusions.
Commercial Relationships: Karla O. VanDick-Sanchez, None;
Pablo J. Guzman-Salas, None; Karla Y. Ruiz-Alvarez, None;
Eduardo Chavez-Mondragon, None
Resident-performed Neodymium: YAG laser posterior
capsulotomy for posterior capsule opacification
Emily M. Zepeda, Jason P. Kam, Joanne C. Wen, Leona Ding.
Ophthalmology, University of Washington, Seattle, WA.
Purpose: To investigate power use and complication frequency
of resident performed Neodymium: YAG (Nd: YAG) posterior
capsulotomy and to compare power use and complication rates of
residents in different stages of training.
Methods: Retrospective analysis was conducted on 175 eyes
from 141 pseudophakic patients diagnosed with posterior capsule
opacification (PCO) who underwent Nd: Yag posterior capsulotomy
from 1/27/2010 to 11/04/2015, at Harborview Medical Center,
Seattle WA by resident physicians. Data was collected on pre/post
best corrected visual acuity, race/ethnicity, pre/post laser intraocular
pressure (IOP), power per shot, number of shots fired and postprocedure complications. Complications included elevated post-laser
IOP at 30-45 minutes (≥8mmHg), lasering structures other than the
PCO, problems focusing the laser, lens subluxation and repeated
procedures. Mean power use and frequency of complications were
evaluated and compared between first year trainees and senior
residents.
Results: The mean total power used for all residents was 111.6 ± 91.0
mJ and the mean power per shot was 1.8 ± 2.0 mJ. The total power
use for first year trainees versus senior residents (second and third
year trainees) did not differ significantly (112.8 ± 87.7 mJ versus
111.1 ± 93 mJ respectively, p=0.9). The mean presenting visual acuity
was LogMar 0.73 ± 0.54, (Snellen 20/107), which improved to a
mean of LogMar 0.51 ± 0.51 (Snellen 20/64) post procedure. The
total complication rate was 16% (28/175), including: IOP spikes in
2.3% (4/175), lasering structures other than the PCO 1.7% (3/175),
problems focusing the laser in 1.7% (3/175), lens subluxation in .6%
(1/175) and repeated procedures in 9.7% (17/175). The complication
rates did not differ with increasing training.
Conclusions: The total power used and complication rates did not
differ between residents in different years of training. The results
of this study suggest that residents at any level of their training
demonstrate procedural proficiency. The results also indicate
that resident performed posterior capsulotomies are successful in
improving visual acuity and have a low complication rate consistent
with previously published data.
Commercial Relationships: Emily M. Zepeda, None;
Jason P. Kam, None; Joanne C. Wen, None; Leona Ding, None

Session 145 Cataract surgery_ Optimizing IOL selection

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