Standard PRK vs. CustomVue:Standard PRK vs. CustomVue: A Comparison of Haze A Comparison of Haze

Vasudha A. Panday, Maj, USAF, MC Vasudha A. Panday, Maj, USAF, MC

Charles D. Reilly, Lt Col, USAF, MC, FSCharles D. Reilly, Lt Col, USAF, MC, FS

Wilford Hall Medical CenterWilford Hall Medical Center

Lackland AFB, TXLackland AFB, TX

BackgroundBackground

Development of haze related to depth of Development of haze related to depth of ablation (refractive error)ablation (refractive error)

Post ablation, keratocytes differentiate into Post ablation, keratocytes differentiate into myofibroblasts, cause stromal irregularitymyofibroblasts, cause stromal irregularity

Numerous factors affect myofibroblast Numerous factors affect myofibroblast transformationtransformation

PurposePurpose

To compare the incidence of haze in post-To compare the incidence of haze in post-refractive surgery patients in standard PRK refractive surgery patients in standard PRK versus wavefront guided PRKversus wavefront guided PRK

HypothesisHypothesis Wavefront-guided Wavefront-guided

ablations will cause ablations will cause less stromal less stromal irregularity, leading irregularity, leading to a decrease in to a decrease in corneal hazecorneal haze

MethodsMethods

12,551 eyes12,551 eyes Retrospective analysis of myopic treatmentsRetrospective analysis of myopic treatments 1, 3, 6, 12 months haze data1, 3, 6, 12 months haze data Haze graded on scale of 1-4Haze graded on scale of 1-4 Eyes grouped by pre-op refractions: Eyes grouped by pre-op refractions:

< 4.00 D, 4.00 – 6.00 D, and > 6.00 D< 4.00 D, 4.00 – 6.00 D, and > 6.00 D

ProcedureProcedure

Ablations performed with Ablations performed with VISX S4 laser VISX S4 laser

6 – 6.5 mm optical zone 6 – 6.5 mm optical zone with blend with blend

Amoils brush to remove Amoils brush to remove epithelium to 8mmepithelium to 8mm

Irrigation with cold BSS Irrigation with cold BSS immediately post ablation immediately post ablation

BSCL appliedBSCL applied No prophylactic MMCNo prophylactic MMC

Post-operative RegimenPost-operative Regimen

Flarex QID with 4 Flarex QID with 4 month taper month taper

Ocuflox QID x 7 daysOcuflox QID x 7 days Tetracaine x 24 hours Tetracaine x 24 hours

(“rescue” drop)(“rescue” drop) PO PercocetPO Percocet BSCL removed day 4 BSCL removed day 4

or 7or 7

Total Haze: < 4.00 D Total Haze: < 4.00 D

1 1 MonthMonth

3 3 MonthsMonths

6 6 MonthsMonths

12 Months

Standard Standard PRKPRK

5.7%5.7%

(178/3132)(178/3132)

3.8%3.8%

(91/2374)(91/2374)

3.0%3.0%

(61/2037)(61/2037)

2.2%

(30/1374)

CustomVueCustomVue 4.3%4.3%

(95/2217)(95/2217)

2.2%2.2%

(35/1612)(35/1612)

0.9%0.9%

(10/1091)(10/1091)

0%

(0/536)

P = 0.0231 P = 0.0031 P = 0.0001 P = 0.0001* No haze was significant enough to require treatment

Total Haze: 4.00 D – 6.00 DTotal Haze: 4.00 D – 6.00 D 1 Month

3 Months

6 Months

12 12 MonthsMonths

Standard Standard PRKPRK

6.6%

(271/4130)

4.6%

(142/3120)

5.6%

(150/2692)

3.7%3.7%

(68/1818)(68/1818)

CustomVueCustomVue 4.5%

(125/2794)

2.6%

(53/2031)

1.5%

(21/1396)

0.3%0.3%

(2/683)(2/683)

P = 0.0002 P = 0.0003 P = 0.0001 P = 0.0001* No haze was significant enough to require treatment

Total Haze: 4 – 6 DTotal Haze: 4 – 6 D

0

1

2

3

4

5

6

7

% Haze

One Three Six Twelve

Months

Standard PRK

CustomVue

* No haze was significant enough to require treatment

Total Haze: > 6.00 D Total Haze: > 6.00 D

1 1 MonthMonth

3 3 MonthsMonths

6 6 MonthsMonths

12 12 MonthsMonths

Standard Standard PRKPRK

10.3%10.3%

(20/194)(20/194)

6.9%6.9%

(9/131)(9/131)

25.8%25.8%

(32/124)(32/124)

25.3%25.3%

(20/79)(20/79)

CustomVueCustomVue 5.3%5.3%

(4/76)(4/76)

7.8%7.8%

(4/51)(4/51)

15.0%15.0%

(6/40)(6/40)

5.0%5.0%

(1/20)(1/20)

P = 0.2389 P = 0.7587 P = 0.1984 P = 0.0646* No haze was significant enough to require treatment

ConclusionsConclusions

Less haze seen overall with CustomVue Less haze seen overall with CustomVue treatmentstreatments

Most significant difference at each time point Most significant difference at each time point noted in < 6 D groupsnoted in < 6 D groups

Most likely due to decrease in stromal surface Most likely due to decrease in stromal surface irregularities with wavefront-guidedirregularities with wavefront-guided PRK PRK compared to standardcompared to standard

With larger sample size, may see a significant With larger sample size, may see a significant decrease in haze in larger diopter treatments decrease in haze in larger diopter treatments as wellas well