Laser in situ keratomileusis for myopia and astigmatism: 6 month results

To evaluate the visual and refractive results of laser in situ keratomileusis (LASIK) for mild to moderate myopia with or without astigmatism.

Barnet-Dulaney Eye Center, Phoenix, Arizona, USA.

Data were prospectively collected on 124 consecutive eyes having LASIK over 12 weeks. Eyes with a preoperative spherical equivalent (SE) from -1.35 to -10.00 diopters (D) (mean -4.81 D +/- 2.21 [SD]) and cylinder from 0 to 5.00 D (mean 1.12 +/- 1.12 D) were entered in the study. Thirty-one eyes had spherical corrections. Ninety-three eyes had spherocylinder corrections; preoperative astigmatism in these eyes ranged from 0.50 to 5.00 D (mean 1.47 +/- 1.09 D). Surgery included creation of a corneal flap using an automated microkeratome with a 160 microns plate followed by photoablation on the exposed stromal bed. Photoablation was performed using five zones varying from 5.0 to 6.6 mm in eyes with 6.25 D of myopia or less and with five passes at a 5.0 mm zone in eyes with 6.50 D of myopia or more. Astigmatism was corrected using a single-pass ablation through a 6.0 mm slit of varying diameter.

Six month follow-up was obtained in 89 eyes (72%). All eyes were completely re-epithelialized by the first postoperative day. Uncorrected visual acuity was 20/40 or better in 81% of eyes at 1 day and in 91% at 6 months. At 6 months, the mean SE was -0.35 +/- 0.77 D; 83% were within +/- 1.00 D of plano. Postoperative astigmatism in the 93 eyes having cylinder correction ranged from 0 to 1.22 D (mean 0.38 +/- 0.42 D). No eye lost more than two lines of best spectacle-corrected visual acuity. Three eyes (2%) required surgical intervention for cap problems. Visually significant corneal haze was not observed.

In eyes with myopia with or without astigmatism, LASIK provided rapid visual recovery with satisfactory visual and refractive outcomes. The effect of LASIK on visual function (night glare, contrast sensitivity) awaits further study.