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Corneal irregular astigmatism after hyperopic laser in situ keratomileusis

Shiro Amano¹, Atsuko Nanba, Naoki Hamada

¹Department of Ophthalmology, University of Tokyo School of Medicine, Tokyo, Japan. amanos-tky@umin.ac.jp

|September 15, 2005

Abstract

Purpose:

To evaluate the changes in irregular astigmatism after hyperopic laser in situ keratomileusis (LASIK).

Methods:

In a prospective case series, 15 eyes of 12 patients who had hyperopic LASIK were evaluated. Corneal topography was obtained before and after hyperopic LASIK. Corneal irregular astigmatism (asymmetry and higher-order irregularity) was calculated using Fourier harmonic analysis of the topography data.

Results:

Hyperopic LASIK significantly increased the asymmetry component at 3 (P = 0.0085) and 6 months (P = 0.0307) postoperatively. The mean higher-order irregularity was not significantly changed at any postoperative time-point (P = 0.222). The achieved change in the spherical equivalent was significantly correlated with the post/preoperative ratio of asymmetry (R = 0.695, P = 0.0030).

Conclusion:

Hyperopic LASIK significantly increases the asymmetry component of the cornea, which is correlated with the achieved change in the spherical equivalent.

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