Excimer Laser for Correction of Myopic Astigmatism after Penetrating Keratoplasty

Abstract

The purpose of this study was evaluate effectiveness and safety of excimer laser for the treatment of myopic astigmatism post-penetrating keratoplasty (PKP) with keratoconus. Methods: Three patients (four eyes) who could not tolerate the use of contact lenses received photorefractive keratectomy (PRK) with the Meditec Aesculap Excimer Laser. In these patients, the mean age was 34 years old, previous PKP ranged from 4 to 9 years, uncorrected visual acuity ranged from 20/80 to 20/400, preoperative myopia range from − 0.50 to −6.50 diopters (D), and astigmatism range from −0.50 to −5.00 D. Evaluation occurred preoperatively, as well as at 2 weeks, and 1,3, and six months postoperatively. Included in each evaluation were clinical examination, specular microscopy, contrast sensitivity test and corneal topography measurement.

Results indicate that all patients improved at least three lines on the Snellen Chart. Uncorrected visual acuity range from 20/20 to 20/60. No graft rejections were observed and one patient developed haze at the second month. Specular microscopy did not show any statistically significant changes. Contrast sensitivity showed a decrease for the low and middle spatial frequencies. These results suggest that PRK could be a solution for patients with significant myopic astigmatism after PKP, who cannot tolerate the use of contact lenses; and may even be a solution for those who can tolerate them.