ASTIGMATISM FOLLOWING PHOTOREFRACTIVE KERATECTOMY FOR MYOPIA

BACKGROUND: Astigmatism following photorefractive keratectomy for myop ia has been reported as stable as early as 2 to 3 months. The authors report 36 out of 60 consecutive eyes with variations in the cylindrica l component of their refraction at 6 months after laser treatment. MET HOD: A standard photorefractive keratectomy was carried out on 60 cons ecutive eyes in 52 patients over a 7-month period. The manifest refrac tion of these eyes was followed for 6 months. RESULTS: Thirty-six eyes demonstrated a change in the cylindrical element of their refraction manifested as a change in cylinder power or axis, or both. The mean pr etreatment cylinder power in the group that underwent a change in the cylindrical element was significantly higher than the mean of the grou p where this did not take place. The mean cylinder power change was 0. 75 diopters (D) and in 9 eyes this change was 1.00 D or more. The corr ected and uncorrected postoperative visual acuities were the same in t he two groups. CONCLUSIONS: This observation implies meridional variab ility in the healing process of the anterior cornea following photoref ractive keratectomy.