Search

Purpose: The purpose of this study was to determine whether astigmatism or corneal scarring is mediating the reduced visual acuity among patients with fungal keratitis randomized to corneal cross-linking (CXL)., Design: This was a prespecified exploratory outcome from an outcome-masked, 2 × 2 factorial design, randomized controlled clinical trial., Study Participants: Consecutive patients presented with moderate vision loss from a smear-positive fungal ulcer at Aravind Eye Hospital, Madurai, India., Intervention: Study eyes were randomized to one of 4 treatment combinations using an adaptive randomization protocol. The treatment arms included (1) topical natamycin 5% alone, (2) topical natamycin 5% plus CXL, (3) topical amphotericin B 0.15% alone, and (4) topical amphotericin 0.15% plus CXL. Best spectacle-corrected visual acuity (BSCVA), contact lens over-refraction, and scar size and depth as measured by a masked study ophthalmologist using a standardized protocol were recorded at 3 months. Pentacam Scheimpflug imaging was also obtained at 3 months., Main Outcome Measures: BSCVA and contact lens over-refraction, infiltrate and/or scar size and depth, total astigmatism of the front and back of the cornea, total lower-order and higher-order aberrations of the anterior and posterior cornea, and total densitometry of the anterior, central, and posterior stroma were recorded. We performed a mediation analysis looking at the proportion of the effect of CXL on BSCVA that was mediated through scar size, scar depth, astigmatism and density., Results: BSCVA at 3 months was available for 99 of 111 patients (89%) who had a mean of 0.82-LogMAR (SD 0.68). Three-month infiltrate and/or scar size ( P < 0.001), depth ( P < 0.001), and densitometry ( P = 0.001) were statistically significant predictors of 3-month BSCVA. Astigmatism seemed to mediate 23% of the effect of CXL on BSCVA, whereas scar size mediated 23%, scar depth 17%, and densitometry 7%., Conclusions: Corneal scarring and astigmatism are mediators of worse visual acuity after cross-linking in fungal keratitis. Corneal densitometry may be a helpful cornea-specific variable for clinicians and researchers in determining the effect of corneal scarring on visual acuity in specific patients and as an objective study outcome., Trial Registration: NCT02570321., Competing Interests: The authors have no funding or conflicts of interest to disclose., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)