21 Sept 2007: NASA Approves LASIK Optical Correction of

21 Sept 2007: NASA Approves LASIK Optical Correction of

Optical Correction of Astronauts
21 Sept 2007:
NASA Approves
LASIK
• 75% of flights have a CL wearer
• 53% of all EVAs have either a spectacle
or CL wearer
• Microbial keratitis has occurred
• Staph epi
• Presbyopia is an issue
• 39% of spectacles are multi-focus
Spectacles
Soft Contact Lens
Is LASIK Good Enough?
Conv PRK vs conv LASIK
0.35
High myopia
Moderate
0.3
LogMAR A
Acuity
0.25
0.2
PRK
20/40
20/32
Low
0.15
P
Preop
1M
3M
6M
0.35
0.3
20/40
0.25
0.2
20/32
LASIK
0.15
Preop
1M
3M
6M
Total n=2746
Conventional vs WFG LASIK
Mech Keratome vs Femtosecond
WFG provides better Contrast Acuity
Femto provides better Contrast Acuity
60%
Conventional (n=841)
WFG (n=238)
Loss of ≥ 2 Lines:
Conv
13%
WFG
1.1%
40%
60%
40%
Mechanical (n=381)
Femtosecond (n=269)
Loss of ≥ 2 Lines:
Mech
3.1%
Femto 1.1%
p=0.00
20%
0%
0%
Loss >2 Loss 2
Loss 1
No Chg
Gain 1
Gain 2 Gain >2
Combining technology: Difference in
Night Driving Performance
40
Preop to postop ch
hange in feet
p=0.00
20%
Detection
Identification
30
20
10
-18
-23
Loss >2 Loss 2
Loss 1
No Chg
Gain 1
Gain 2 Gain >2
First Naval Aviator to
undergo LASIK
+31
+20
Better after surgery
0
-10
Worse after surgery
-20
-30
Conventional
n=61
WFG with femto flap
n=39
What Happened Next…
• April 07: NASA MAB meeting
– Recommends approval of LVC based on
improved results of WFG and femtosecond
LASIK
• May 07: USAF approves LASIK
– All aviation categories (tx in AF centers)
– Recommends WFG and femtosecond laser
• Sept 07: NASA approves LASIK for
astronaut applicants
– Preop +4 to -8D MSE, up to 3D cyl
We have entered a new era in laser vision correction
Optical Correction of Astronauts
70%
63%
67%
Distribution of Astronaut Manifest Sphere
30%
Pilots
(n=49)
Mission Spec
(n=89)
Glasses and/or Co
ontacts
33%
None
Glasses and/or Co
ontacts
30%
None
None
37%
ontacts
Glasses and/or Co
Pilots
Combined
(n=139)
Mission Specialists
20%
10%
0%
-4
-3
-2
-1
0
1
• Optical correction of astronauts
• Concerns about LASIK
– Environmental issues
– Quality of vision
• Military studies
• Dec 06: NAMI authorizes LASIK in first
Navy/Marine aviator
NASA Approves
LASIK
2
• Houston, TX, September 21, 2007 -- The
National Aeronautics and Space Agency
(NASA) approved PRK and LASIK for
astronaut applicants
• At least 1 year has passed since the date
of the procedure with no permanent
adverse after effects.
• An operative report on the surgical
procedure will be requested.
• over 50% of rejected astronaut applicants
have been dismissed due to poor vision.
• The NASA endorsement of Lasik and
PRK iis a bi
big thing,"
thi " says Smith
S ith L
L.
Johnston, a NASA physician who
oversees astronauts' medical standards.
Dr. Johnston says the reversal will open
the door to many "sharp people" who in
the past would have been ruled out.
Distribution of Astronaut Manifest Sphere
Distribution of Astronaut Manifest Sphere
30%
40
Pilots
30
Pilots
Mission Specialists
Mission Specialists
20%
20
10%
10
0
0%
-3
-2
-1
0
1
-4
2
-3
Spectacle Type
-2
-1
0
1
2
Contact Lenses
45
42%
40
Single Vision
61%
PAL
33%
Multi Focus
39%
Bifocal
53%
Trifocal
14%
% of Spectacle W
Wearers
-4
35%
35
RGP
12%
30
25
23%
20
15
SCL
88%
10
5
0
Pilot
(N=31)
Mission Specialist Combined
(N=62)
(N=93)
Combined
EVA MODE OF CORRECTION
Flight Eyewear Usage
No vision
correction
22%
Contact
Lenses
No Rx
47%
(29)
10%
Specs
31%
(19)
BF
32%
SV
47%
PAL
21%
CL
22%
(14)
68%
Spectacles
STS - 95 to 103
61 Flights
374 Crewmembers
RGP
21%
Toric
21%
75% of flights have a contact lens wearer
Sphere
57%
N = 65 EVA’s (33 Crewmembers)
Age: 35 - 58 years
Time: April 1991 - June 1999
Missions: STS 37 - 96
1 Case of Infiltrative Keratitis
• Followed 1 Month Post Mission
• Cultured Staph-Epi
• Conventional Toric Extend Wear SCL
Is the Flap Stable Enough?
Is the Quality of Vision good
enough?
Force Gauge ((lbs)
100
80
60
40
Flap Displacement
400 knot ejection
20
Halo
0
50
150
250
350
450
550
Gun Chamber Pressure (lbs/in2)
650
Laurent JM et al. J Cataract Refract Surg. 2006. 32:1046-51
Night Driving Performance after
Conventional LASIK
Conv LASIK vs PRK Preop
Low
Moderate
High
(<-3.0D)
(-3.0 to -5.5D)
(>-5.5D)
-3.76
-6.22
604
151
-3.90
-6.20
613
298
cPRK (747 patients)
MSE
-1.79
n (eyes)
720
cLASIK (635 patients)
MSE
-2.02
n (eyes)
360
Pedestrian
Simulated rural driving at 55mph
NDS cLASIK Results With Glare
Change
Detection
Change
Identification
Business
-35*
-41*
Pedestrian
-33*
-35*
Traffic
-16*
-15*
Business Sign with Glare
50%
Worse postop
40%
Better postop
34%
30%
1 sec = 81 ft
at 55mph
20%
10%
0%
2%
-3
5%
-2
-1
0
1
2
3
Identification Difference (post – preop) in Seconds
* Significantly different, p ≤ 0.05
N=105
Pupil Diameter vs Business ID
800
600
ID Distance (ft)
400
r2=0.000
200
3
4
5
6
7
Low light pupil diameter
8
9
Wavefront Guided LASIK
LASIK MSE Distribution: 3M
LASIK Uncorrected Acuity: 3M
WFG is more predictable (p<0.001)
100%
WFG
Conv
60%
Mean ± SD
40%
WFG
+0.01 D ± 0.31
Conv
-0.03 D ± 0.42
50%
88%
68%
75%
Matched dataset
WFG n = 238
Conv n = 841
96%
88%
39%
30%
20%
25%
0%
-1.50
-1.00
-0.50
0.00
0.50
1.00
1.50
MSE (D)
LASIK Change in BCVA: 3M
Mean ± SD
+0.4 ± 0.6
+0.2 ± 0.6
WFG
Conv
Improvement
(p<0.01)
50%
20/16
20/20
• 1 Excimer
– VISX Star S4 CustomVue
Lost ≥1 Line
WFG = 4%
Conv = 9%
25%
20/12.5
What is the Best
Microkeratome to
perform LASIK in
Aviators?
WFG provides better results (Chi2=70.2, p<0.001)
75%
0%
• 2 Surgeons
• 3 Keratomes
– Mechanical: Amadeus & Hansatome
– Femtosecond: Intralase
0%
-4
-3
-2
-1
0
1
2
3
4
Change in Lines of Acuity
UCVA – 1 Day PostOp
Mean ± SD
Mechanical
Femtosecond
(n=346)
(n=240)
-0.03 ± 0.11
-0.08 ± 0.10
100%
89%
82%
UCVA
p=0.00
Create the LASIK flap with a
femtosecond laser
72%
75%
51%
50%
27%
Correct refractive error with
WFG ablation
25%
10%
0%
20/12.5+
LASIK in Aviators
“Best of the Best”
20/16+
20/20+
20/40+
Conclusion
• Huge benefit of RS in aviators
– Improved performance
– Select higher quality students
• New era in vision standards
• PRK program successful
– Slow visual recovery is more than nuisance
• “Best of the Best” LASIK
– Unparalleled safety and effectiveness
– Faster return to the cockpit
– Now offered at all Navy centers