Evaluation of Astigmatism Induced by Spherical LASIK.

Lim, Hyun Taek; Tchah, Hungwon

Original Article

Journal of the Korean Ophthalmological Society 1999;40(2):354-360.
Published online February 1, 1999.

Evaluation of Astigmatism Induced by Spherical LASIK.

Hyun Taek Lim, Hungwon Tchah

Department of Ophthalmology, College of Medicine, University of Ulsan, Asan Medical Center.

구면 절제 LASIK 수술에 의해 유발된 난시량 평가

임현택(Hyun Taek Lim),차흥원(Hung Won Tchah)

Abstract

The purpose of the study is to evaluate the induced astigmatism after spherical LASIK operations. A total of 36 eyes of 33 patients were treated with a Automated keratome and VISX 20/20 excimer laser. The postoperative 1 month, 3 months, and 6 months astigmatic refractive outcomes were compared with the initial refraction by vector analysis (Alpins and Holladay method). Subjective astigmatic refraction reduced from a mean of 0.48D+/-SD 0.49D(range, 0 to 1.75D) to 0.34D+/-SD 0.54D(range, 0 to 2.0D) at postoperative 6 months.Surgically induced astigmatism(SIA) had a mean of 0.53+/-0.69D(range: 0~2.49D) at 1 month, 0.49+/-0.61D(range: 0~2.79D) at 3 months, 0.62+/-0.72D(range: 0~3.14D) at 6 months follow-up. Mean SIA increased with increasing preoperative astigmatism by 0.45D SIA for every 0.5D of preoperative cylinder(Correlation coefficient: 0.618). The authors show that spherical LASIK corrections can induce significant astigmatic change, particularly if a large amount of preoperative astigmatism is present.

Key Words: Astigmatism;Spherical LASIK;Surgically induced astigmatism