Photorefractive keratectomy for compound myopic astigmatism with the MEL-70 G-scan excimer laser

PURPOSE. To assess the safety, efficacy, predictability and stability of photorefractive keratectomy in compound myopic astigmatism with a moderate and high cylinder component. METHODS. Photorefractive keratectomy was done in 42 eyes with compound myopic astigmatism with the spherocylindrical algorithm of the MEL-70 excimer laser, with wide ablation zones. RESULTS. Spherical equivalent refraction changed from -4.19 +/- 1.65D to -0.05 +/- 0.31D, refractive cylinder from -2.01 +/- 0.71D to -0.09 +/- 0.20D and mean sphere from -3.22 +/- 1.76D to -0.02 +/- 0.26D. Mean uncorrected visual acuity rose from 0.12 +/- 0.17 to 0.91 +/- 0.10. No eye lost lines of spectacle-corrected visual acuity. The safety index was 1.03 and the efficacy index 0.98. Six months from the treatment all eyes were within +/-1D, 8.9% of eyes were within 0.50D and 44% were plano of target refraction. Refractive and topographical stability were achieved between one and three months after treatment. Transient haze was observed between one and three months after PRK. CONCLUSIONS. Photorefractive keratectomy with the MEL-70 excimer laser to correct myopic astigmatism was a safe and effective procedure with good stability at six months' follow-up. Refractive and visual outcome confirmed that excellent predictability can be expected.