Cornea-sparing laser in situ keratomileusis: ablation on the flap.

Purpose: To evaluate the safety and efficacy of laser ablation on the flap as a treatment for a refractive error.

Setting: Laser Sight Centres, Sydney, Australia.

Methods: In this noncomparative case series, 142 treatments were performed in 98 patients using cornea-sparing laser in situ keratomileusis (LASIK) with ablation of the corneal flap and, in some cases, also the stromal bed for spherical equivalent (SE) refractive errors from -0.50 diopter (D) to -12.38 D. The procedure was performed as a primary treatment in 104 eyes, an initial enhancement in 32 eyes, and a second enhancement in 6 eyes. Data were extracted for analysis by retrospective review of patients' charts.

Results: After LASIK, the mean SE was -0.20 D +/- 0.47 (SD) (range +0.87 to -2.35 D) excluding eyes with monovision. The 6 eyes with monovision had a mean SE of -1.90 D with myopia of -1.70 D (range -1.00 to -3.00 D) and mean astigmatism of -0.37 D (range 0 to -0.75 D). Excluding eyes with monovision, 97% of eyes achieved an uncorrected visual acuity of 6/12 or better and 64% of eyes, better than or equal to 6/6. Ninety-six percent were within +/-1.0 D of the intended correction (SE). The safety index was 1.02 and the efficacy index, 0.8.

Conclusions: Laser ablation of the corneal flap achieved good visual results and enabled preservation of the posterior corneal stroma. This technique may aid the prevention of corneal keratectasia following LASIK.