Topical Losartan In Corneal Fibrosis: A Clinical, Topographic, And Densitometric Longitudinal Analysis

Corneal scarring poses significant challenges in ophthalmic care, often leading to permanent visual impairment. Topical losartan has emerged as a promising therapy for corneal fibrosis by inhibiting TGF- β signaling and promoting apoptosis of myofibroblasts, key mediators of scar formation. Although preclinical studies and human case reports suggest its efficacy and safety, clinical data remain limited. This study aims to evaluate the efficacy and safety of topical losartan for corneal scarring through clinical, topographic, and densitometric outcomes over an 8-months follow-up in real-world practice, representing one of the first prospective longitudinal clinical evaluations of topical losartan in corneal fibrosis.

A prospective study was conducted at a tertiary hospital (Unidade Local de Saúde de Coimbra, Coimbra, Portugal) between April 2025 and February 2026.

Inclusion criteria included corneal opacities of any etiology, refractory to or unsuitable for other treatments except corneal transplantation. Topical losartan (0.8 mg/mL) compounded by the hospital pharmacy was prescribed six times daily. Baseline variables included age, sex, etiology and duration of corneal opacity (months). Patients were evaluated at baseline and at 2, 4, 6 and 8 months after starting treatment. At each visit, best-corrected visual acuity (BCVA), slit-lamp examination, corneal tomography, densitometry and adverse events were documented. Linear mixed models with repeated measures were used to analyze longitudinal changes, accounting for within-subject correlations.

Nineteen eyes (58% females; mean age 39.17±22.88 years) from 18 patients were included. Infectious causes predominated (58%, n=11) with a median scar duration of 15.5 months (IQR, 7.25–24.25). Mean BCVA improved from 0.53 logMAR at baseline to 0.36 logMAR at 8-months (p=0.108). Central corneal densitometry decreased from 3.505 to 3.329 log GSU (p=0.002), specifically within the 2–6 mm zone (3.518 to 3.298, p<0.001) over time. Anterior densitometry in 0–2 mm zone showed a transient increase at 2 months (3.761 to 3.904, p=0.004), before stabilizing. Kmax decreased throughout follow-up (51.50 to 48.46 D; p=0.001), with no other topographic changes. No adverse effects were reported. Two patients discontinued treatment due to compliance issues.

Topical losartan appears to be a safe and effective therapy for corneal scarring. Treatment was associated with significant improvements in densitometry and a trend towards visual improvement, suggesting a reduction in stromal fibrosis. This structural improvement, combined with a reduction in Kmax may reflect corneal surface regularization secondary to stromal remodeling. While the transient increase in anterior densitometry at two months may indicate ongoing collagen remodeling or transient epithelial changes during early reparative phases, the subsequent stabilization suggests a shift toward biomechanical normalization. Further clinical trials are needed to determine optimal treatment duration, frequency, and storage conditions.