Analysis of astigmatism of 1 238 cases myopic patients who were scheduled for refractive surgery

Objective To analyze the astigmatism in a myopic population who were scheduled for refractive surgery in Linyi and learn the composition and distribution of astigmatism. Methods This was a cross-sectional analysis of 1 238 patients (2 476 eyes) in a youth population who underwent excimer laser treatment in the Eye Hospital from May 2011 to October 2012. Measurements were taken of total astigmatism, corneal astigmatism, lens astigmatism and astigmatism axis. Results The prevalence of astigmatism in these 2 476 eyes was 65.14%, with an average total astigmatism of 0.58±0.62 D, corneal astigmatism accounted for the largest percentage with a mean of 1.06±0.59 D, and the mean lens astigmatism was 0.58±0.40 D. For total astigmatism, the percent of with-the-rule astigmatism was 49.39%, against-the-rule astigmatism was 8.19%, oblique astigmatism was 7.56%, and 34.86% had no astigmatism. For corneal astigmatism, the ratio for with-the-rule astigmatism was 85.26%, against-the-rule astigmatism was 3.19%, oblique astigmatism was 6.99%, and 4.56% had no astigmatism. For lens astigmatism, the ratio of with-the-rule astigmatism was 4.16%, against-the-rule astigmatism was 73.10%, oblique astigmatism was 7.19%, and 15.55% had no astigmatism. Simple corneal astigmatism accounted for 13.25%, simple lens astigmatism accounted for 1.78%, and mixed factors caused astigmatism in 81.99%. There was no astigmatism in 2.99% for each previous category. Conclusion Corneal astigmatism is a major factor in the total astigmatism of a youth population who underwent excimer laser treatment. With-the-rule astigmatism is the main category in both total astigmatism and corneal astigmatism. Key words: Astigmatism; Youth; Myopia; Refractive surgical procedure