Optical coherence tomography-guided transepithelial phototherapeutic keratectomy for the treatment of anterior corneal scarring.

Purpose: To report the visual and anatomic outcomes of a novel technique for the management of anterior corneal scarring using optical coherence tomography (OCT)-guided transepithelial phototherapeutic keratectomy (transepithelial PTK).

Design: Retrospective, consecutive case series.

Methods: The charts of 22 patients with anterior corneal scarring associated with irregularities in the Bowman layer who had undergone transepithelial PTK according to a novel protocol were reviewed. The protocol consisted of a preoperative OCT-measured depth-of-treatment calculation, followed by a dual excimer laser treatment profile set to achieve the desired refractive outcome while eliminating or reducing corneal scarring. The primary outcomes were change in best spectacle-corrected visual acuity (BSCVA) and change in corneal topography indices at 4 months after ablation.

Results: BSCVA (in logMAR) improved from a mean of 0.82 (0.61-1.02; 95% confidence interval) preoperatively to a mean of 0.40 postoperatively (0.19-0.61) (P = 0.0070). All patients gained a minimum of 1 line of BSCVA postoperatively. Preoperative and postoperative corneal topographic indices showed significant improvement in corneal cylinder (P = 0.0173) and projected visual acuity (P = 0.0261) but not in the surface asymmetry index (P = 0.0849) or the surface regularity index (P = 0.0543). Postoperative spherical equivalent averaged 0.78 diopters (0.49-1.07) of error from the intended target refractive outcome. No complications were associated with the treatment, and no patients required or desired subsequent treatment with either repeat PTK or with more invasive surgery such as lamellar or penetrating keratoplasty.

Conclusions: OCT-guided transepithelial PTK using a dual ablation excimer laser profile can provide favorable results as well as predictable refractive outcomes in the treatment of corneal scarring associated with Bowman layer irregularities. Future investigations are warranted to further validate the technique reported in this study.