Phototherapeutic Keratectomy for Irregular Astigmatism Secondary to Limbal Fibrosis

Abstract

Purpose: : To describe the results of Phototherapeutic keratectomy (PTK) in patients with irregular astigmatism due to limbal fibrosis.

Methods: : Three eyes of 3 patients with irregular astigmatism secondary to an unspecific epithelial corneal fibrosis involving an area of the limbal zone were treated by PTK-assisted anterior keratectomy after a manual epithelial debridment ("fibrosis pealing"; FP) of the affected area. PTKs were performed with a VisX S4 excimer laser. Best spectacle corrected visual acuity (BCVA), refraction, and videokeratography (VK) were evaluated before and after the treatment.

Results: : The mean pre- and postoperative best spectacle corrected visual acuities (BCVA) were 0.2 ± 0.2 and 0.2 ± 0.3 respectively, on a logarithm of the minimal angle of resolution (log MAR) scale. Yet 2 of 3 eyes gained one Snellen line of BCVA. Preoperative VKs showed irregular astigmatism pattern that was corrected in all eyes despite the fact that no astigmatic photorefractive correction was performed.

Conclusions: : Treatment of eyes with irregular astigmatism related to limbal fibrosis (or "limbal cheloid" or "subepithelial dysplasia") by PTK-assisted FP showed significant improvement of irregular astigmatism revealed by VK. The procedure did not compromise BCVA. We assume that the fibrosis induces astigmatism. Limbal fibrotic diseases may have immunological origin and there may be immunological risk factors as cause to predispose for these diseases. Collection of a larger patient series for obtaining more conclusive results is underway.

Keywords: refractive surgery • aberrations • cornea: epithelium