Efficacy of astigmatism correction after transepithelial photorefractive keratectomy

Objective To evaluate the efficacy of astigmatism correction after transepithelial photorefractive keratectomy (transPRK). Methods The data of 64 eyes of 32 cases with myopic astigmatism from May 2017 to Feb. 2018 were analyzed retrospectively. They received transPRK and followed up for 3 months. All patients were divided into 2 groups, low astigmatism group, 43 eyes with -0.25D--0.75 D, and medium to high astigmatism group, 21 eyes with 1.00D--2.75D. The diopter parameters were collected before and 3 months after transPRK. Postoperative astigmatism related vector parameters were compared between the two groups with standard vector analysis. Results The difference in absolute value of error of angle (t=2.547, P=0.014), correction ratio (t=2.117, P=0.039) and error ratio (t=3.679, P=0.001) were statistically significant between the two groups after operation. There was a positive correlation between overall error rate and intended refractive correction (r=0.339, P<0.01), but there was no significant correlation between correction rate and intended refractive correction. Conclusion The outcome of astigmatism correction after transPRK is closely related to the degree of astigmatism before surgery. It is necessary to adjust the target value of astigmatism correction and exclude other factors that affect astigmatism correction in clinical practice. Key words: Analysis, vector; Keratectomy, transepithelial, photorefractive; Astigmatism; Myopia