Refractive Surgery In the Military

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Now we have
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Laser Procedures

• PRK
• LASIK

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Photorefractive Keratectomy (PRK)

• Excimer laser reshapes cornea
• Very precise
• For myopia, hyperopia, astigmatism
• Good results safety

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LASIK

• Microkeratome flap
• Excimer laser removes precise amount corneal
  tissue
• For myopia, astigmatism and hyperopia
• Rapid popularity worldwide

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LASIK
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Center for Refractive Surgery
PRK vs. LASIK

• PRK
• Day one Oowww!
• Less surgical risk
• Slower recovery
• 80 20/20
• Haze possible
• No flap

• LASIK
• Day one Wow!
• Greater surgical risk
• Quicker recovery
• 80 20/20
• No haze
• Flap

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Do we need refractive surgery in the military
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OPERATIONAL VISION CORRECTION

• Over 1/2 million soldiers, sailors and airmen
• 40 require optical correction
• Annual cost of optical corrective devicesvast

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OPERATIONAL VISION CORRECTION
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GLASSES

• Traditional way to correct all forms of
  refractive error
• Relatively inexpensive
• Few complications
• Very precise

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GLASSES

• Disadvantages

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GLASSES

• Disadvantages

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GLASSES

• Disadvantages
• Limit range of vision
• Fogging, scratched
• Broken or lost
• Compatibility problems-- with night vision
  goggles, protective mask inserts, etc.

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CONTACT LENSES

• Advantages
• Cosmesis
• Increased FOV
• Less minificationbetter vision in myopia

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CONTACT LENSES

• Disadvantages
• Difficult to clean in field environment
• May lead to infection
• Problematic in chemical environments
• Dislodge with G-forces

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REFRACTIVE SURGERY

• All-weather 24/7 correction
• Compatible with equipment
• Increased soldier confidence(no broken or fogged
  glasses)
• Increased survivability(lost glasses casualty)
• Improved quality of life---higher retention

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ARMY POLICY

• AR 40-501 prohibits entry with history of
  refractive surgery, but
• Waiver policy (OTSG May 2000)allows for PRK or
  LASIK if---
• At least 6 months since surgery
• Meet AR 40-501 vision standards

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ARMY POLICY

• No visual side effects affecting daily activities
• Refractive error stability
• Post-LASIK excluded from HALO, Flight, Diving
  and SF training
• Post-PRK excluded from Aviation

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Center for Refractive Surgery
WRESP Warfighter Refractive Eye Surgery Program

• WRESP -- limited resource available to commanders
  to enhance mission readiness

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Center for Refractive Surgery
WRESP Warfighter Refractive Eye Surgery Program

• WRESP -- limited resource available to commanders
  to enhance mission readiness
• MEDCOM establishing WRESP Laser Eye Centers in
  MTFs designated by the DCSOPS

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Center for Refractive Surgery
WRESP Warfighter Refractive Eye Surgery Program

• WRESP -- limited resource available to commanders
  to enhance mission readiness
• MEDCOM establishing WRESP Laser Eye Centers in
  MTFs designated by the DCSOPS
• WRESP Centers Operational -- Ft. Bragg Planned
  -- Ft Campbell, Ft Hood, Tripler AMC, Landstuhl
  RMC

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Center for Refractive Surgery
WRESP Warfighter Refractive Eye Surgery Program

• WRESP -- limited resource available to commanders
  to enhance mission readiness
• MEDCOM establishing WRESP Laser Eye Centers in
  MTFs designated by the DCSOPS
• WRESP Centers Operational -- Ft. Bragg Planned
  -- Ft Campbell, Ft Hood, Tripler AMC, Landstuhl
  RMC,
• DHS allocates appointments to supported units

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Center for Refractive Surgery
WRESP Warfighter Refractive Eye Surgery Program

• WRESP -- limited resource available to commanders
  to enhance mission readiness
• MEDCOM establishing WRESP Laser Eye Centers in
  MTFs designated by the DCSOPS
• WRESP Centers Operational -- Ft. Bragg Planned
  -- Ft Campbell, Ft Hood, Tripler AMC, Landstuhl
  RMC,
• DHS allocates appointments to supported units
• Unit commands maintain by-name 3-month list

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Center for Refractive Surgery
WRESP Soldier Selection Criteria Warfighter
Refractive Eye Surgery Program

• Assigned to unit with mission at line-of-battle
  or behind hostile lines

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Center for Refractive Surgery
WRESP Soldier Selection Criteria Warfighter
Refractive Eye Surgery Program

• Assigned to unit with mission at line-of-battle
  or behind hostile lines
• 1st priority -- SOC Infantry, Armor, Field
  Artillery

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Center for Refractive Surgery
WRESP Soldier Selection Criteria Warfighter
Refractive Eye Surgery Program

• Assigned to unit with mission at line-of-battle
  or behind hostile lines
• 1st priority -- SOC Infantry, Armor, Field
  Artillery
• 2nd priority-- CSS assigned to Division or
  Separate Brigade

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Center for Refractive Surgery
WRESP Soldier Selection Criteria Warfighter
Refractive Eye Surgery Program

• Assigned to unit with mission at line-of-battle
  or behind hostile lines
• 1st priority -- SOC Infantry, Armor, Field
  Artillery
• 2nd priority-- CSS assigned to Division or
  Separate Brigade
• Other service members -- space available

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Center for Refractive Surgery
WRESP Soldier Selection Criteria Warfighter
Refractive Eye Surgery Program

• Assigned to unit with mission at line-of-battle
  or behind hostile lines
• 1st priority -- SOC Infantry, Armor, Field
  Artillery
• 2nd priority-- CSS assigned to Division or
  Separate Brigade
• Other service members -- space available
• At least 18 mo remaining on AD or with
  reenlistment

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Center for Refractive Surgery
WRESP Soldier Selection Criteria Warfighter
Refractive Eye Surgery Program

• Assigned to unit with mission at line-of-battle
  or behind hostile lines
• 1st priority -- SOC Infantry, Armor, Field
  Artillery
• 2nd priority-- CSS assigned to Division or
  Separate Brigade
• Other service members -- space available
• At least 18 mo remaining on AD or with
  reenlistment
• At least 12 mo remaining with same/similar unit

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Center for Refractive Surgery
WRESP Soldier Selection Criteria Warfighter
Refractive Eye Surgery Program

• Assigned to unit with mission at line-of-battle
  or behind hostile lines
• 1st priority -- SOC Infantry, Armor, Field
  Artillery
• 2nd priority-- CSS assigned to Division or
  Separate Brigade
• Other service members -- space available
• At least 18 mo remaining on AD or with
  reenlistment
• At least 12 mo remaining with same/similar unit
• Must return for follow-up as specified

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Center for Refractive Surgery
Womack Army Medical Center Warfighter Refractive
Eye Surgery Program

• AD Army, Navy and Marines at Ft Bragg
• To benefit Warfighter(USASOC, 18th Airborne)
• 1500 pts/year (3000 procedures) 125/month
• USASOCPRK only
• All othersLASIK or PRK
• LASIK disqualifying for SOC schools(HALO, scuba,
  SFQC, SERE)
• Aviatorsnot eligible

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NAVY POLICY

• Similar to ARMY for PRK
• Excludes LASIK unless in research protocol
• WRESP Centers at San Diego, Portsmouth, Bethesda
• Four others planned

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AIR FORCE POLICY

• Waiver for PRK only
• Aviation and special duty
• Includes 200 rated aviators and 100 student
  aviators per year
• WRESP Center at Wilford Hall planned for AF
  Academy and Wright-Patterson

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Center for Refractive Surgery
Completed Navy Research Initial Evaluation of
PRK Bottom line

• 80 -- 20/20 UCVA
• 60 -- 20/16 UCVA
• gt90 -- 20/20 on re-treatment
• Overall -- safe and effective

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Center for Refractive Surgery
Completed Navy Research Visual Recovery in
PRK Bottom Line

• How long before 20/20 uncorrected VA?- 40 at 1
  week- 81 at 4 weeks- 81 at 12 weeks
• Prolonged recovery, transient CS loss
• Stable refraction in 6 weeks to 3 months
• Extended recovery period in PRK

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Center for Refractive Surgery
Completed Navy Research Pupil Size, Glare and
Halos In PRK Bottom line

• No correlation pupil size symptoms
• No correlation pupil size pre- / post-op
  visual performance differences
• Symptoms correlated with degree of myopia

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Center for Refractive Surgery
Completed Navy Research Psychiatric Factors and
Patient Satisfaction After PRK Bottom line

• Overall 92 happy with outcome
• The greater the depression before PRK-- less
  happy and more regret after PRK
• Older patients less happy, more regret

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Center for Refractive Surgery
Completed Navy Research NVG Performance and
PRK Bottom line

• Slight VA and CS decrease at 2 weeks
• Returned to normal at 4 weeks
• Transient loss of NVG performance

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Center for Refractive Surgery
Completed Navy Research Quality of Vision
Prolonged Exposure to Altitude Bottom line

• RK, PRK, LASIK groups
• All slight corneal swelling (12-34 microns)
• Hyperopic shift large in RK, slight in PRK/LASIK
  (0.2 0.3 D)
• Slight decrease in uncorrected and best corrected
  vision

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Center for Refractive Surgery
Completed Navy Research Night Driving Simulation
After PRK Bottom line

• Distance for detection of road signs
• Detection distances decreased in symptomatic eyes
  those with greater light scatter
• Promising functional approach

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Center for Refractive Surgery
Completed Navy Research Vector Analysis Outcome
of Astigmatic PRK Bottom line

• 20/20 UCVA in 73
• Slight undercorrection of astigmatism common
• Induced cylinderrare

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Center for Refractive Surgery
Completed Navy Research Initial Evaluation of
LASIK In Navy Bottom line

• 92 -- 20/20 UCVA at 12 months
• 70 -- 20/16 UCVA
• Slight decrease in CS, resolved 3 months
• 1 displaced flap at I day post-op
• Rapid return to duty

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Center for Refractive Surgery
Ongoing/Future Naval Research

• Visual performance after PRK and LASIK
• Initial evaluation of (INTACS)
• Hyperopic PRK
• Normative values for contrast sensitivity
• Wavefront sensing
• Cyclogyl vs tropicamide in refractive surgery
• NEI refractive surgery questionnaire
• PRK to retain ametropic Naval aviators

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Center for Refractive Surgery
USAF PRK Study

• 80 non-aviators, 20 controls 30 months
• Comprehensive ophthalmological baseline
• Unique operational testing
• Contrast sensitivity, color vision, NVGs, glare
  disability, corneal haze detection
• Subsets PRK at altitude PRK under
  high Gz loads PRK and cockpit
  visual simulation

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Center for Refractive Surgery
Ongoing Air Force Research Evaluation of PRK In
Air Force Bottom line

• Nearly 100 subjects all myopic
• Safe and effective thus far
• Mean values at 6 monthsUCVA
  20/16BSCVA 20/14BSC SLCT 1.21
• Loss BSCVA and CS in some

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Center for Refractive Surgery
Ongoing Air Force Research High Low Contrast
Vision In PRK Bottom line

• Pre-op BSC vs post-op UC
• Decrease on each charthigh contrast VA 2
  letterslow contrast VA 5 lettersSLCT 11
  letters
• 24 require Rx for 20/20 in one eye

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Center for Refractive Surgery
Ongoing Air Force Research Contrast Sensitivity
Glare in PRK Bottom line

• Post-op decrease for middle/low SFs
• More marked decrease with glare and dilation
  which persisted up to 1 year
• Likely due to refractive transition zone

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Refractive Surgery In Military Aviation
Center for Refractive Surgery Walter Reed Health
Care System Washington, DC
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Center for Refractive Surgery
FAA Policy on Refractive Surgery

• PRK and LASIK authorized without waiver, provided
  that
• Post-operative condition has stabilized
• No significant adverse effects or complications
• Pilot meets FAA vision standards(Primary
  standardcorrected to 20/20 each eye)

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Center for Refractive Surgery

• Ongoing study--PRK in rated aviators with
  promising results thus far
• Initiating study of pilots trainees at least
  three months post-op to PRK

Naval Aviation PRK Research
Air Force PRK Research

• 80 non-aviators, 20 controls 30 months
• Basic vision and operational testing
• Altitude, high Gz loads, cockpit simulation
• Promising results thus far

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Center for Refractive Surgery
Air Force Waiver for PRK

• Effective 2 Aug 00
• Includes Aviation Special Duty
• Strict clinical criteria follow-up
• 200 rated aviators/year 100 pilot candidates
• Must have PRK done at approved DoD site
• Myopia only -1 to 5.5 up to 3D astigmatism

No Current Navy or Army Aviation Waiver for PRK
or LASIK Unless In Research Protocol
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Center for Refractive Surgery
Refractive Surgery Army Aviation USAARL
Accession Study

• Initiated Feb 01
• Visual flight performance of flight school
  applicants who had laser surgery
• Enrollment criteria3 months post-op, stable
  refraction, class 1 flight standards
• 100 LASIK, 100 PRK, 100 controls
• Goaldetermine if PRK/LASIK waiverable

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Center for Refractive Surgery
Refractive Surgery Army Aviation WRAMC/USAARL
Accession Study

• To begin Mar 02
• Prospective study of visual flight performance
  of pilot trainees
• Refractive surgery at WRAMC Center
• 40 PRK, 40 LASIKmatched for degree of
  pre-operative refractive error
• Goals--determine if PRK/LASIK waiverable expand
  applicant pool identify factors to minimize risk
  and maximize performance

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Center for Refractive Surgery
Refractive Surgery Army Aviation USAARL/WRAMC
Rated Aviator Study

• Study approved Jan 02
• UH-60 Black Hawk rated aviators
• Refractive surgery at WRAMC Center
• 40 PRK, 40 LASIKmatched for degree of
  pre-operative refractive error
• Comparison between flight performance before
  surgery (with spectacle Rx) and performance
  after surgery (without Rx)
• LASIK vs. PRK

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Center for Refractive Surgery
Current Results
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Night Vision Performance and Visual Acuity After
Photorefractive Keratectomy
Barbara OKane, PhD, Raymond Stefanik, James
Stevens, Prem Subramanian, MD, PhD,Jeff Rabin,
OD, PhD, Robert Bauer, MD, PhD, and Kraig Bower,
MD
Center for Refractive Surgery Walter Reed Army
Medical Center Washington, DC US Army CECOM
RDEC Night Vision Electronic Sensors
Directorate Fort Belvoir, VA
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Introduction

• Vision often returns tonormal after refractive
  surgery(eg, PRK or LASIK).
• Despite reports of decreasednight vision
• Tests of night vision are lacking.

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Introduction

• Military operations--at night
• Evaluation of efficacy safety of refractive
  surgery for combat
• Must include night vision performance testing.

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Research Purpose
To evaluate ? visual acuity through
night vision goggles and ? detection
of low contrast targets before and after PRK.
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Summary of Methods

• 19 Special Operations soldiers received PRK.
• All near-sighted before PRK (uncorrected VA
  20/40 to 20/400).
• VA evaluated through NVGs(before 3 months
  after PRK).
• Detection of low contrast targets(before 3
  months after PRK).

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• Before PRK NVG VA was decreased when tested
  without glasses.
• After PRK NVG VA without glasses as good or
  better than pre-operative VA with glasses.

Results (next slide)
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NVG Acuity and PRK
180
worse
160
140
Visual acuity (20/...)
120
100
80
60
40
mean 1SEn 19 binocular data
better
20
Full moon
1/4 moon
Starlight
Overcast Starlight
Night sky condition
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Results (next slide) Acuity at Low Contrast

• Decrease in VA with decreasing letter contrast.
• No difference between pre- and post-op VA.
• Relation between VA contrast remained the same
  in all conditions.

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Acuity and Contrast In PRK
160
worse
140
120
Visual acuity (20/...)
100
80
All values with best correction
60
40
mean 1SEn 19
better
20
.1
1
10
100
Contrast ()
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Conclusions

• After PRK, NVG performance(without glasses) as
  good or betterthan performance before
  surgery(with glasses).
• May translate to improved performance for
  soldiers unable to wear glasses in combat.

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Visual Performance In Soldiers One Year After
PRK Preliminary Results
Center for Refractive Surgery Walter Reed Health
Care System
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Methods

• VA tested across range of contrasts (1.25 - 100)
• Small target CS
• Spatial and temporal CS(sine-wave 2 alternative
  forced choice)
• Photopic and mesopic testing
• With/without glare

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High Contrast Visual Acuity
D V N Z R
H N F V D
F U P V E
P E R Z U
Logarithmic progression in letter size
F H P V E
Z R F N U
P R Z E U
F V P Z D
U P N H F
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Low Contrast Visual Acuity
D V N Z R
H N F V D
F U P V E
P E R Z U
Rendition of 10 contrast
F H P V E
Z R F N U
P R Z E U
F V P Z D
U P N H F
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Low Contrast Visual Acuity
D V N Z R
H N F V D
F U P V E
P E R Z U
Rendition of 2.5 contrast
F H P V E
Z R F N U
P R Z E U
F V P Z D
U P N H F
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Low Contrast Visual Acuity
D V N Z R
H N F V D
F U P V E
P E R Z U
Rendition of 1.25 contrast
F H P V E
Z R F N U
P R Z E U
F V P Z D
U P N H F
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Visual Acuity and Contrast
1.2
Mesopic
worse
Photopic
20/200
0.9
Glare
Visual acuity (logMAR)
0.6
20/85
Mesopic (nighttime)
0.3
Photopic (daytime)
20/22
0.0
better
20/14
-0.3
.1
1
10
100
Letter contrast (percent)
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1000
Spatial Contrast Sensitivity
One Year After PRK (minimum contrast to detect
pattern as a function of pattern fineness)
100
Photopic (daytime)
Contrast sensitivity
(minimum contrast for detection)
Mesopic (nighttime)
10
(coarse ---------- pattern fineness
------------------ fine)
1
0.1
1
10
100
Spatial frequency (cycles/deg)
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100
Temporal Contrast Sensitivity
One Year After PRK (minimum contrast to detect
flicker as a function of flicker rate)
Photopic (daytime)
Contrast sensitivity
10
(minimum contrast for detection)
Mesopic (nighttine)
(slow ---------- flicker frequency
------------------ fast)
1
0.1
1
10
100
Temporal frequency (cycles/sec)
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A New Test for Measuring Glare Disability in
Refractive Surgery
Center for Refractive Surgery Walter Reed Health
Care System Washington, DC
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Introduction

• LASIK and PRK-- effective for correction of
  refractive error
• Despite efficacy of refractive surgery
• Many patients complain of glare
• Particularly at night

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Introduction

• Conventional glare testing--bright glare source
  under photopic conditions
• Paradoxical improvement in vision
• Due to constriction of the pupil
• Which decreases effects of peripheral aberrations

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New Test of Glare Disability

• New approach to quantify glare disability
• Which overcomes problems of conventional tests
• By using contrast-modulated stimulus
• Under reduced luminance to encourage pupil
  dilation

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New Test of Glare Disability

• Small letter contrast test(20/25 letters varied
  in contrast)
• Viewed at low luminance (3 cd/m2)
• With and without diffuse surrounding glare
• Chart luminance remains constant with/without
  glare
• Minimal (lt1mm) change in pupil size

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Without glare
Viewed at low luminance
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With glare
Viewed at low luminance
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Results
Glare Disability Mesopic CS 1-Year After PRK

• Shift from photopic to mesopic...8-line decrease
  in CS
• Addition of glare...further decrease 3-lines

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Glare Disability 1-Year After PRK
1.5
mean2SE, n18 eyes
1.2
Log small letter contrast sensitivity
0.9
8 lines
0.6
0.3
3 lines
0.0
Photopic
Mesopic
MesGlare
Test condition
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Results
Glare Disability Mesopic CS 1-Year After PRK

• Infrared pupillometry under mesopic conditions...
• Larger pupils--lower CS,both with/without glare
• Suggests adverse effect of peripheral aberrations

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Mesopic CS, Glare Pupil Size 1-Year After PRK
Mesopic
MesGlare
Log small letter contrast sensitivity
Mesopic pupil size (mm)
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Center for Refractive Surgery
Future Research
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Center for Refractive Surgery
Future research will assess the impact of
refractive surgery on

• Performance with night vision devices

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Center for Refractive Surgery
Future research will assess the impact of
refractive surgery on

• Performance with night vision devices
• Night firing

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Center for Refractive Surgery
Future research will assess the impact of
refractive surgery on

• Performance with night vision devices
• Night firing
• Land navigation

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Center for Refractive Surgery
Future research will assess the impact of
refractive surgery on

• Performance with night vision devices
• Night firing
• Land navigation
• Helmet-mounted displays

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Center for Refractive Surgery
Future research will assess the impact of
refractive surgery on

• Performance with night vision devices
• Night firing
• Land navigation
• Helmet-mounted displays
• Flight training

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Center for Refractive Surgery
Future research will assess the impact of
refractive surgery on

• Performance with night vision devices
• Night firing
• Land navigation
• Helmet-mounted displays
• Flight training
• Night flight

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Center for Refractive Surgery
Future research will assess the impact of
refractive surgery on

• Performance with night vision devices
• Night firing
• Land navigation
• Helmet-mounted displays
• Flight training
• Night flight
• Performance of experienced aviators

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Center for Refractive Surgery
Beyond 20/20
In Pursuit ofSuper-Normal Vision
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Center for Refractive Surgery
Beyond 20/20 In Pursuit of Super-Normal Vision

• In standard eye exam, we test for--near-sightedne
  ss, far-sightedness, astigmatism
• Additional optical aberrations(e.g., coma,
  spherical aberration)
• Also have a significant impact on vision.

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Center for Refractive Surgery
Beyond 20/20 In Pursuit of Super-Normal Vision

• Objective technique now exists for comprehensive
  measurement of the optics of the eye
• Shack-Hartmann wavefront aberrometry
• Based on the shape of the wavefront of light
  reflected from the eye.

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Center for Refractive Surgery
Beyond 20/20 In Pursuit of Super-Normal Vision

• Beam of light is reflected from the eye
• Through a micro-lens array producing a spot image
  array of reflected light.
• Computer analysis determines relative
  displacement of each spot image
• Used to compute local slope character of the
  wavefront of light.

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Center for Refractive Surgery
Beyond 20/20 In Pursuit of Super-Normal Vision

• The analyzed wavefront is used to derive a
  correction profile
• Which can be used toguide laser eye surgery.
• FDA studies nearly complete verifying the
  efficacy safety of this approach.

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Center for Refractive Surgery
Beyond 20/20 In Pursuit of Super-Normal Vision

• Our research development includes
• State-of-the-art laser with eye tracking
• Coupled with wavefront technology
• Unique measures of visual performance
• To achieve optimal vision for soldier civilian
  alike.

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Center for Refractive Surgery
Beyond 20/20 In Pursuit of Super-Normal Vision

• A correction which minimizes optical aberrations
  will improve.
• Visual acuityas much as 2x.
• Small target contrast sensitivity(as much as
  7x).
• And performance at night when pupil becomes large.

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Center for Refractive Surgery
Beyond 20/20 In Pursuit of Super-Normal Vision
What will Super-Normal Vision look like??
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Before correction of aberrations
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After correction of aberrations