Original article
Optical Coherence Tomography–Guided Transepithelial Phototherapeutic Keratectomy for the Treatment of Anterior Corneal Scarring

https://doi.org/10.1016/j.ajo.2013.06.026Get rights and content

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.

Section snippets

Methods

The Southwest Retina Specialists institutional review board (IORG0007600/IRB00009122) approved this retrospective chart review of consecutive cases in patients who underwent OCT-guided transepithelial PTK for anterior corneal scarring between January 2011 and February 2013. All research components adhered to the tenets of the Declaration of Helsinki and were conducted in accordance with human-subject research regulations and standards.

Results

A total of 22 eyes of 20 patients met criteria for inclusion in the study. The various underlying pathologies responsible for the corneal scarring are detailed in Table 1. The mean age of the subjects was 58.6 years (50.4–66.8; 95% CI); 59% were male and 41% female. Table 2 details the pertinent findings of the study. BSCVA (in logMAR) improved from 0.82 (0.61–1.02) to 0.40 (0.19–0.61) (P = 0.0070). The mean baseline epithelial thickness was 51.6 μm, and the mean baseline maximum crater depth

Discussion

Anterior corneal scarring with crater formation presents a significant treatment challenge for the clinician, and currently no consensus exists regarding the best treatment option. The ideal strategy should aim not only to eliminate the corneal opacity but also to improve the overall anatomic shape of the cornea, thereby minimizing postoperative irregular astigmatism and improving BSCVA. The marked distortion and flattening present on corneal topography in patients with anterior corneal

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