Myoung Joon Kim, MD / Sara Yoon, MDMyoung Joon Kim, MD / Sara Yoon, MD

Tracy Purcell, PhD / David J Schanzlin, Tracy Purcell, PhD / David J Schanzlin, MDMD

LLaser In Situ Keratomileusis versus aser In Situ Keratomileusis versus Photorefractive Keratectomy Photorefractive Keratectomy for the Treatment of Myopia for the Treatment of Myopia

with CustomVue Platformwith CustomVue Platform

No author has a financial or proprietary interest in any material or method mentioned.

CustomVue platform provides a wavefront-guided treatmentCustomVue platform provides a wavefront-guided treatment to correct refractive errors.to correct refractive errors.

Literature shows:Literature shows:

LASIKLASIKMinimal postoperative pain Faster Minimal postoperative pain Faster visual recoveryvisual recoveryLess regressionLess regressionNo hazeNo hazeFlap-related complications Flap-related complications Interface-related complications Interface-related complications Corneal biomechanical instabilityCorneal biomechanical instability

PRKPRKSafe and effectiveSafe and effectivePostoperative painPostoperative painSlow visual recovery Slow visual recovery Corneal hazeCorneal haze

Previous studiesPrevious studies

Few studies have compared LASIK and PRK Few studies have compared LASIK and PRK

using CustomVue Platform.using CustomVue Platform.§§

PURPOSEPURPOSE To compare the outcomes of LASIK and PRK To compare the outcomes of LASIK and PRK

in wavefront-guided treatment of low to moderate myopiain wavefront-guided treatment of low to moderate myopia

using CustomVue Platfromusing CustomVue Platfrom

§ Wavefront-guided laser in situ keratomileusis using the WaveScan system for correction of low to moderate myopia with astigmatism: 6-month results in 277 eyes. J Cataract Refract Surg 2005. CustomVue laser in situ keratomileusis for myopia and myopic astigmatism using the Visx S4 excimer laser: Efficacy, predictability, and safety. J Cataract Refract Surg 2006. Wavefront-guided laser in situ keratomileusis in the treatment of high myopia by using the CustomVue wavefront platform. Cornea 2008.

Retrospective control-matched designRetrospective control-matched design

Duration: Jan. 2006 ~ Dec. 2007Duration: Jan. 2006 ~ Dec. 2007

Preoperative manifest sphere ≤ -6 D, Cylinder ≤ 2 DPreoperative manifest sphere ≤ -6 D, Cylinder ≤ 2 D

Matching criteria: Sphere within ± 1 D, Cylinder within ± 1 DMatching criteria: Sphere within ± 1 D, Cylinder within ± 1 D

Age within 10 years Age within 10 years

Primary procedure performed in the same yearPrimary procedure performed in the same year

Exclusion criteria: Preoperative BSCVA < 20/25Exclusion criteria: Preoperative BSCVA < 20/25

Follow-up duration less than 3 months Follow-up duration less than 3 months

ProcedureProcedure

One surgeon (DJS)One surgeon (DJS)

LASIK flap creation with IntraLaseLASIK flap creation with IntraLase

Myopic wavefront-guided treatment targeted at planoMyopic wavefront-guided treatment targeted at plano

Mitomycin 0.02% used in PRKMitomycin 0.02% used in PRK

Laser platform: VISX STAR S4 IR (AMO, Santa Ana, CA)Laser platform: VISX STAR S4 IR (AMO, Santa Ana, CA)

Wavefront analysisWavefront analysis

Between postoperative 1 and 3 monthsBetween postoperative 1 and 3 months

WaveScan (AMO, Santa Ana, CA)WaveScan (AMO, Santa Ana, CA)

Outcome Analysis Software v4.0 (Outcome Analysis Software,Outcome Analysis Software v4.0 (Outcome Analysis Software,

Inc, San Diego, CA) Inc, San Diego, CA)

46 eyes matched (23 eyes per each group)46 eyes matched (23 eyes per each group)

Patients agePatients age LASIKLASIK group 35.5±9.7 years group 35.5±9.7 years PRKPRK group 36.2±12.5 years group 36.2±12.5 years PP=0.92=0.92

Preoperative refractive errors

LASIKLASIK group groupSPH -4.10±1.48 D (range -1.75 ~ -6.00)SPH -4.10±1.48 D (range -1.75 ~ -6.00)CYL 0.86±0.53 D (range 0 ~ +1.75)CYL 0.86±0.53 D (range 0 ~ +1.75)

PRKPRK group groupSPH -3.97±1.45 D (range -1.00 ~ -6.00)SPH -3.97±1.45 D (range -1.00 ~ -6.00)CYL 0.82±0.51 D (range 0 ~ +1.75) CYL 0.82±0.51 D (range 0 ~ +1.75) PP=0.55 for SPH, 0.77 for CYL=0.55 for SPH, 0.77 for CYL

Mean UCVA at 1 month, LogMARMean UCVA at 1 month, LogMAR

LASIKLASIK

0.03±0.17 0.03±0.17

(LogMAR 0.03 = 20/21.3)(LogMAR 0.03 = 20/21.3)

Mean UCVA at 3 months, LogMARMean UCVA at 3 months, LogMAR

LASIKLASIK

0.00±0.15 0.00±0.15

(LogMAR 0.00 = 20/20.0)(LogMAR 0.00 = 20/20.0)

Mean UCVA at last follow-up, LogMARMean UCVA at last follow-up, LogMAR

LASIKLASIK mean 11.3 monthsmean 11.3 months

-0.08±0.07 -0.08±0.07 (LogMAR -0.08 = 20/16.7)(LogMAR -0.08 = 20/16.7)

PRKPRK

0.04±0.08 0.04±0.08 (LogMAR 0.04 = 20/22.0)(LogMAR 0.04 = 20/22.0) PP=0.75=0.75

PRKPRK

0.03±0.15 0.03±0.15

(LogMAR 0.03 = 20/21.3)(LogMAR 0.03 = 20/21.3) PP=0.61=0.61

PRKPRK mean 11.6 monthsmean 11.6 months

-0.07±0.10 -0.07±0.10 (LogMAR 0.03 = 20/17.2(LogMAR 0.03 = 20/17.2) ) PP=0.57=0.57

Cumulative UCVA (Snellen)Cumulative UCVA (Snellen)

LASIKLASIK PRKPRK

% %

Among higher-order aberrations, only rms of total higher-order aberration showed statistically significant change (P=0.025).

Coma and spherical aberration showed tendency to be increased (P=0.054, 0.055).

LASIKLASIK

PRKPRK

Among higher-order aberrations, none of them showed statistically significant change after PRK (P>0.05).

Both femtosecond laser LASIK and PRK showed similar good visual outcomes in wavefront-guided treatment of myopia using CustomVue Platform.

In LASIK, higher-order aberrations increased significantly postoperatively. Out of components of higher-order aberration, coma and spherical aberration showed tendency to be increased. Radially symmerical component (spherical aberration) may be induced by laser ablation pattern and radially asymmetric component (coma) may be related with flap of LASIK (hinge itself , opaque bubble layer around hinge at the time of flap creation by femtosecond laser).

CONCLUSIONCONCLUSION