Factors influencing the need for enhancement after laser in situ keratomileusis

Abstract

Purpose: To confirm that enhancements after primary laser in situ keratomileusis (LASIK) are effective in dealing with residual refractive errors, and to determine if any variables prior to or during the primary LASIK procedure predisposed eyes to require subsequent enhancement.

Methods: A retrospective study of eyes undergoing primary LASIK with the VISX S2 or S3 laser and Hansatome microkeratome between January 1, 2000 and January 1, 2002 was done. Of the 393 eyes of 207 patients, 58 eyes (14%) underwent enhancement within a 16-month window of the primary procedure. Statistical comparisons were made between enhanced (n = 37) and non-enhanced (n = 148) patients, and enhanced (n = 48) and non-enhanced (n = 303) eyes, treated for myopia only.

Results: In comparing the primary LASIK parameters of enhanced to non-enhanced eyes in myopic patients, no significant difference was found in right vs left eye, season of the primary treatment, preoperative astigmatism, pachymetry, or amount of attempted astigmatism correction. A multivariate logistic regression analysis revealed that male gender, patient age over 45 years, and a history of recent rigid contact lens use within 6 months of primary LASIK were significantly associated with the need for enhancement.

Conclusion: Enhancements were an effective way of dealing with residual refractive errors after primary LASIK. Age greater than 45 years or a history of recent rigid contact lens use were significantly associated with the need for enhancement in patients with myopia or myopic astigmatism.