Factor Analysis of Refractive Outcome in LASIK

ABSTRACT

We intended to identify preoperative factors associated with refractive outcome of LASIK.We have performed LASIK for correction of 3.25 to 19.00 diopter of myopia using Aesculap-Meditec, Mel 60.Three principal outcomes of LASIK on 75 patients (104 eyes)were examined : (1)Efficacy (2)Predictability (3)Stability.Multiple logistic regression was used to test for independent associations of multiple preoperative factors with each of three outcomes. Lesser astigmatism was associated with increased efficacy (odds ratio=0.580).Greater optical zone was associated with increased efficacy (0.289) and with lesser likelihood of instability of refraction (0.272).Greater attempted correction was associated with decreased predictability, specifically with undercorrection (4.545 :8.25-14.75D / 21.430 :> or=15.00D).Greater average SimK was associated with decreased likelihood of instability of refraction (0.602). In conclusion.preoperative factors associated with postoperative uncorrected visual acuity are amount of astigmatism and optical zone size.Predictability is associated with attempted correction.Stability is associated with average SimK and optical zone size.Such information may help guide patient selection, determine timing of fellow eye treatment, and suggest changes in the laser treatment algorithm for individual patients.