Transepithelial Photorefractive Keratectomy For Irregular Corneas With Varying Initial Conditions

Transepithelial excimer laser treatment is an established procedure for smoothing corneal irregularities. The aim of this prospective study is to present the treatment results, taking into account the preoperative baseline conditions.

Medical University of Vienna, Department of Ophthalmology and Optometry

For this prospective study, 46 severely aberrated corneas with an RMS-HOA (root mean square higher order aberration) error of 1.0 to 3.0 D.eq (equivalent dioptres) were included. Prior to surgery, aberrations up to the 6th order were recorded using the MS-39 (Schwind) and divided into different groups according to the degree and type of aberration. The ablation profile took into account aberrations up to the 6th order as well as the mean epithelial thickness in the central 3 mm area. The treatment was performed with the Amaris 1050 (Schwind). The follow-up time was six months after treatment.

Spherical aberration, coma and trefoil were reduced to a statistically significant extent. Secondary astigmatism was reduced, but not statistically significantly. Taking into account the initial situation, patients with high spherical aberration in particular benefited from this treatment in terms of a lower postoperative RMS-HOA value.  

In this setup, the preoperative extent of spherical aberration, coma and trefoil are the decisive parameters for predicting the benefits of transepithelial excimer laser treatment in highly aberrated corneas.