Risk Factors For Retreatment In Refractive Surgery

Determine risk factors for laser enhancement after primary refractive surgery.

Hopital Fondation Rothschild – Refractive Surgery Department

1,245 eyes operated of refractive surgery were included in this study. Eyes were divided into 2 main groups: eyes undergoing photorefractive keratectomy (PRK) and eyes undergoing laser in situ keratomileusis (LASIK). In each of these 2 groups, eyes were further classified into either a non-enhanced group, or an enhanced group that includes eyes who needed laser retreatment post-operatively. Eyes were also separated into either a myopic or myopic astigmatic group, or a hyperopic and hyperopic astigmatism group. A total of 20 parameters were measured for each eye pre-operatively and per-operatively and compared between the different subgroups.

1245eyes were included with 57.8%females and 42.8%males. Mean age was 33+/-9years. 84%(N=1045) were treated for myopia or myopic astigmatism(cyl<2D), 11.6%(N=145) for hyperopia or hyperopic astigmatism(cyl<2D),and 4.42%(N=55) for pure astigmatism(cyl>2D). 18%(N=225) underwent PRK and 82%(N=1020) LASIK. 0.96%(N=12) needed laser enhancement. Factors significantly affecting laser enhancement risk were higher age(p=0.016),higher pre-operative cyl(p=0.003),hyperopia(p=0.001),larger iris size(p=0.045),higher laser shots done(p=0.006),and longer laser treatment time(p=0.041). Sex,cyl axis,pre-op pachymetry,residual stromal bed, treatment ablation zone diameter,and per-op apex decentration were not significantly different,all ametropias confounded.

This study includes several parameters affecting refractive surgery retreatment risk that were not previously reported. We hope that these data will help clinicians adapt their treatment and prevent the need for refractive enhancement.