Transcript April 2013 - iLASIK for Nasa and the US Military

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Night Carrier Operations
Spectacles
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Soft Contact Lens
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Contact Lenses
Is LASIK OK in the Aerospace Environment?
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Refractive Surgery in Naval Aviators
“Retention” Study
785 aviators treated with PRK
>45,000 flight hours
>12,000 landings
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Complications
Corneal haze (9 aviators)
– Late haze with loss of best vision
– Treated with steroids
– Grounded but all eventually resumed flying
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“Accessioning” Study
Students allowed into flight training that
previously underwent PRK
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Student Naval Aviator Accessioning Study:
Cumulative Attrition Rate
Phase
Attrition
(160th-195th weeks)
Primary
Intermediate +
Advanced
PRK
Control
PRK
Control
6.9%*
10.7%
1.4%*
5.1%
* Significantly lower
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These two studies profoundly changed
DoD vision standards
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The “Achilles' Heel” of PRK
• Prolonged visual recovery
– Minimum aviator ‘down’ time is 3 months
• LASIK offers faster recovery
– Faster return to cockpit
• Qualification to land on an aircraft carrier is
ONE week!
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Is the Flap Stable Enough?
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Force Gauge (lbs)
Flap Displacement
400 knot ejection
Halo
Gun Chamber Pressure (lbs/in2)
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Is the Quality of Vision good
enough?
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Change in 5% Contrast Acuity
LogMAR Acuity
High myopia
Moderate
PRK
20/32
20/40
LASIK
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Low
20/40
20/32
Wavefront Guided LASIK
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Conventional vs WFG LASIK
WFG provides better Contrast Acuity
Loss of ≥ 2 Lines:
Conv
13%
WFG
1.1%
p=0.00
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What is the Best
Microkeratome to
perform LASIK in
Aviators?
• 1 Excimer
– VISX Star S4 CustomVue
• 2 Surgeons
• 3 Keratomes
– Mechanical: Amadeus & Hansatome
– Femtosecond: Intralase
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Mech Keratome vs Femtosecond
Femto provides better Contrast Acuity
Loss of ≥ 2 Lines:
Mech
3.1%
Femto 1.1%
p=0.00
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Femtosecond-Mechanical Comparison:
% of eyes achieving 20/20 UCVA
100%
Femtosecond
95%
90%
Microkeratome
96%
93%
93%
93%
89%
85%
96%
86%
83%
80%
Matched retrospective analysis
1,000 eyes IL
1,000 eyes MK
Myopia < 3.0D
Cyl <= 0.75D
75%
1 Day
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1 Week
1 Month
3 Month
1
88%
100%
81%
0.75
0.65
66%
75%
0.5
WFG
WFG
Fourier
0.34
0.31
2003
2005
50%
% 20/16 UCVA
MSE Standard Deviation
Improving Outcomes
54%
0.45
0.25
Star S2
Star S3
1999
2001
0
Year
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n = 1168
3 mo postop
Comparison of Night Driving
Performance After WavefrontGuided and Conventional LASIK
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Preop to postop change in feet
Preop to Postop Difference in
NDS Performance with Glare
Improved after surgery
Worse after surgery
Conventional
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WFG with femto flap
LASIK
“Best of the Best”
Create the LASIK flap with a
femtosecond laser
Correct refractive error with
WFG ablation
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Optical Express 1 mo. UCVA after iLASIK
(24,928 eyes of 13,283 consecutive pts)
Age: 18 to 69 yrs
Sph: -0.25 to -6.0D
Cyl: 0.0 to -6.0D
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First Naval Aviator to
undergo LASIK
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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
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We have entered a new era in laser vision correction
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