Excimer lasers and enhancement procedures

52 EW REFRACTIVE SURGERY
August 2015
Device focus
Excimer lasers and
enhancement procedures
by Michelle Dalton EyeWorld Contributing Writer
When coupled with the new iDesign high resolution aberrometer, true wavefront-guided
treatments with the VISX S4 laser are producing great results with laser vision correction,
according to Dr. Dell.
Source: Steven Dell, MD
For surgeons with only
an occasional need for
an excimer laser, here are
some of the major bells
and whistles to consider
H
igh-volume refractive practices are well versed in the
features today’s excimer
lasers provide—and how
those features are providing even better patient outcomes.
But for the premium lens cataract
surgeon who may be performing
infrequent corrections for residual
refractive errors, what are the most
important features to consider?
Excluding obvious parameters such
as physical footprint, EyeWorld asked
several leading refractive surgeons
for their opinions.
First and foremost, they said,
remember that most often the
enhancements are very minor and
most platforms will be sufficient.
“I usually prefer standard treatments because these are low corrections, and since there is an IOL in
the eye, the refraction and typical
parameters such as axial length and
corneal curvature have been decoupled,” said John Berdahl, MD, in
practice at Vance Thompson Vision,
Sioux Falls, S.D., who uses both the
VISX (Abbott Medical Optics, Abbott
Park, Ill.) and WaveLight (Alcon,
Fort Worth, Texas) for these purposes. “I think the biggest key is a good
stable refraction, and I have grown
to favor LASIK over PRK because I
think this older population has a
tendency to have more epithelial
irregularities that affect the refraction and can become unmasked
with PRK.”
When evaluating laser systems,
Vance Thompson, MD, director of
refractive surgery, Vance Thompson
Vision, said it’s important to know
the data—what percentage is within
±0.25 D and ±0.5 D for low corrections, what percentage results in
20/20. When considering buying a
laser, “make sure the laser is FDA-approved for the enhancement label,
or it’s an off-label use,” he said.
For Steven Dell, MD, founder of
Dell Laser Consultants, Austin, Texas, the occasional refractive surgeon
may not need to master LASIK.
“They can very simply do PRK,
which is a whole lot simpler to
learn, and because of the low or
relatively low prescriptions that are
being treated, nomogram adjustments are not particularly important,” Dr. Dell said. “Let’s say you’re
treating 0.75 D of residual myopia,
and you miss by 10%. That’s a clinically irrelevant number. If you were
treating –7 D and were off by 10%,
that’s visually significant.”
However, any surgeon who is
implanting premium IOLs needs to
have some sort of laser vision correction solution available “or they’re
not going to get any significant traction in their practices,” he said.
Keeping “everything simple” is
the key to enhancing these patients,
said Uday Devgan, MD, in private practice, Devgan Eye Surgery,
clinical professor, UCLA, and chief
of ophthalmology, Olive View-UCLA
Medical Center. Among his top
3 pearls: wait 3 months for the
refraction to stabilize; the patient
Monovision continued from page 50
“Presbyopes have not always
been accepting of this type of correction,” Dr. Pallikaris explained.
“However, two-thirds of presbyopes
can accept monovision [LASIK]
today. Overall, anyone presenting
with presbyopia can be corrected by
a refractive procedure 85% of the
time.” EW
References
1. Reilly CD, Lee WB, Alvarenga L, et al.
Surgical monovision and monovision reversal
in LASIK. Cornea. 2006;25:136–138.
2. Johannsdottir KR, Stelmach LB. Monovision:
a review of the scientific literature. Optom Vis
Sci. 2001;78:646–651.
3. Garcia-Gonzalez M, Teus MA, HernandezVerdejo JL. Visual outcomes of LASIK-induced
monovision in myopic patients with presbyopia. Am J Ophthalmol. 2010;150:381–386.
4. Alarcón A, Anera RG, Villa C, Jiménez del
Barco L, Gutierrez R. Visual quality after monovision correction by laser in situ keratomileusis in presbyopic patients. J Cataract Refract
Surg. 2011;37:1629–1635.
Editors’ note: Dr. Pallikaris has
financial interests with Presbia
(Irvine, Calif.).
Contact information
Pallikaris: [email protected]
may benefit from a YAG laser
treatment if there’s any PCO or
capsular fibrosis; and patients with
hyperopia after cataract surgery may
do better with a piggyback IOL (or
IOL exchange) since hyperopic PRK
is “not that great.” A small degree
of hyperopic LASIK (up to +2 D) is
acceptable, he said; the most critical
point: The refraction that makes the
patient happy in trial frames is “the
exact treatment that we want to do
with the excimer laser.”
When it comes to the nitty-gritty of what’s on the laser, Sonia H.
Yoo, MD, professor of ophthalmology, Bascom Palmer Eye Institute,
Miami, said she prefers a fast, small
spot laser that will give a smooth ablation, and considers a pupil-tracking feature necessary as it keeps the
ablation centered.
“I like the ability to change the
optical zone in order to spare tissue
for higher ablations on thinner corneas. An aberrometer that is paired
to the laser gives the added advantage of decreasing data entry error
and treating higher order aberrations,” she said.
Dr. Dell believes the new
aberrometer device on the iDesign
system (Abbott Medical Optics) is
the “premier, top shelf type of technology that is available for dedicated
refractive surgeons” as it essentially
incorporates an aberrometer with a
built-in topographer unit, as well as
a pupillometer and an autorefractor.
But the iDesign system’s features
make it almost ideal for the “occasional user who just wants to touch
up a premium IOL case,” he said.
“The technology is a more robust
version of what physicians have
been using for wavefront-guided
treatments for years.”
What technique to use
If the manifest refraction best corrected image quality is “super crisp”
and patients have a “normal tear
film and cornea (including thickness),” then either PRK or LASIK is
an effective choice, Dr. Thompson
said.
“But if we know that tear film
abnormalities may be an issue, and
we treat that tear film and the refraction is still not crisp and topography
is normal, I start to think about
occult anterior basement membrane
dystrophy as the cause of surface
irregularity leading to reduced image
August 2015
quality. PRK can be such a beautiful
enhancer in these situations to treat
both the residual refractive error
and improve the best corrected and
uncorrected image quality,” Dr.
Thompson said.
Dr. Devgan said for the occasional user, “don’t worry about doing a ‘custom’ treatment or a ‘wave
scan’ reading—the actual refraction
that makes the patient happy is
more important.” Before the initial
surgery, Dr. Devgan recommends
choosing a higher power IOL if
in doubt since myopic ablations
are more accurate than hyperopic
ablations.
Dell has financial interests with Abbott
Medical Optics and Bausch + Lomb.
Dr. Devgan has financial interests with
Alcon and Bausch + Lomb.
newNAVEX3_EW_isl.qxd:Layout 1
Contact information
Berdahl:
[email protected]
Dell: [email protected]
7/8/15
11:01 AM
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EW REFRACTIVE SURGERY 53
Devgan: [email protected]
Thompson:
[email protected]
Yoo: [email protected]
Open-access?
Roll-on/roll-off options?
Occasional-use surgeons might
consider buying a used laser, but
the service contracts will still equate
to around $30,000–$50,000 a year.
Partnering also makes sense, as the
refractive expert is likely to offer his/
her services at a deep discount, Dr.
Devgan said. In Beverly Hills, one
open access facility serves 30 different ophthalmologists, who book
time accordingly, he said.
One last caveat: Surgeons must
be certified before using a laser, so
novice users should plan on having
4–6 eyes that need enhancements
on the day of training, Dr. Devgan
said.
Open-access is a good option for
surgeons who laser infrequently, Dr.
Yoo said. “The costs of owning and
maintaining a laser can be defrayed
while still being able to provide the
service to your patients.”
Most refractive surgeons or refractive centers “would welcome an
open-access surgeon who wants to
use their laser occasionally for a feeper-case,” Dr. Dell said. “It adds to
their bottom line, and there are very
few laser vision correction centers
that are doing the volume that they
would like to do right now.”
If surgeons are at a point where
volume is dictating “perhaps dozens
of cases a month or maybe 15 to 20
cases a month, those practices might
consider a mobile, roll-on/roll-off
laser,” Dr. Dell said, and several
companies offer that option. EW
Editor’s note: Drs. Berdahl, Thompson,
and Yoo have financial interests with
Abbott Medical Optics, Alcon, and
Bausch + Lomb (Bridgewater, N.J.). Dr.
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June 3, 2015
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