Anatomic Biomarkers Predict Poor Presenting Visual Acuity in Infectious Keratitis

Infectious keratitis, the leading cause of corneal blindness, disproportionately affects developing countries. We examined risk factors for poor presenting visual acuity in a rural Indian population.

We conducted a cross-sectional study of patients ≥16 years old with active infectious keratitis at SNC Hospital, a tertiary eye hospital in north India, from June to November 2024. Variables collected were demographics, clinical features, and anatomic findings on slit-lamp examination. Binomial logistic regression measured association of variables with best-corrected visual acuity (BCVA) ≤20/200. Significant univariable associations were incorporated into a multivariable model.

Among 667 patients with keratitis (mean age: 50.3 ± 15 years), 497 (74.5%) presented with VA ≤20/200. Independent risk factors for poor VA included older age (prevalence ratio [PR] 1.01/year, 95% CI 1.00-1.01, p<0.001), bacterial infection (PR 1.12, 95% CI 1.03-1.23, p=0.009), polymicrobial infections (PR 1.13, 95% CI 1.01-1.26, p=0.027), larger epithelial defect (PR 1.38, 95% CI 1.12-1.71, p=0.042 with epithelial defect diameter >6mm), posterior stromal infiltrate (PR 1.22, 95% CI 1.09-1.36, p<0.001), endothelial plaque (PR 1.13, 95% CI 1.00-1.26, p=0.043), central infiltrate location (PR 1.26, 95% CI 1.14-1.38, p<0.001) and hypopyon (PR 1.28, 95% CI 1.18-1.39, p<0.001). Travel distance, time to presentation, and clinical risk factors were not independently associated with poor VA.

Anatomic features including larger epithelial defects, deep stromal infiltrates, endothelial plaque, central location, and hypopyon were the strongest predictors of poor VA. These findings highlight the utility of anatomic features for identifying eyes at risk for severe outcomes and serving as biomarkers in future clinical trials.