Long-term outcomes of optical coherence tomography-guided transepithelial phototherapeutic keratectomy for the treatment of anterior corneal scarring.

Abstract

To report the long-term outcomes of optical coherence tomography (OCT)-guided transepithelial phototherapeutic keratectomy (PTK) for the management of anterior corneal scarring. The charts of 60 patients (64 eyes) who underwent OCT-guided transepithelial PTK for anterior corneal scarring were retrospectively reviewed. The procedure involved a preoperative OCT-measured depth of treatment calculation to reduce or eliminate corneal scarring, followed by a combined myopic and hyperopic transepithelial excimer laser treatment profile established to attain the desired refractive result. The main outcome measures consisted of change in best spectacle-corrected visual acuity (BSCVA), change in OCT-measured parameters, and change in corneal topography indices. The mean follow-up was 41.0 weeks (range: 12-117 weeks). BSCVA improved from a mean of 0.77 logMAR (0.65-0.89) preoperatively to a mean of 0.34 logMAR (0.21-0.46) postoperatively (p<0.0001). Comparison of preoperative and postoperative corneal topographic indices showed significant improvement in all parameters analysed: corneal cylinder (p=0.0008), surface asymmetry index (p=0.0054), surface regularity index (p=0.0047) and projected visual acuity (p=0.0045). Postoperative spherical equivalent averaged 0.91 (±0.71) dioptres of error from the intended target refractive outcome. Two patients required penetrating keratoplasty and one patient underwent repeat PTK during the study interval. The OCT-guided transepithelial PTK technique described in this study can deliver positive long-term results and predictable refractive outcomes in the treatment of anterior corneal scarring.