Early alterations in central corneal epithelial thickness after ocular chemical burns

To evaluate central corneal epithelial thickness (CCET) during the early healing phase after ocular chemical burns using anterior segment optical coherence tomography (AS-OCT) and to assess its relationship with clinical parameters.

This retrospective study included 35 patients with chemical ocular burns treated between 2020 and 2024. CCET and central corneal stromal thickness were measured by AS-OCT one month after injury. Clinical data included burn severity according to the Dua classification, initial and final visual acuity (VA), epithelialization time, and treatment modality (medical therapy, autologous serum drops, or amniotic membrane transplantation [AMT]). Results were compared with healthy control group. Correlation and subgroup analyses were performed.

The mean age of patients was 40.2 ± 19.6 years, and 74.3% were male. Alkaline agents caused 88.6% of injuries. The mean epithelialization time was 14.0 ± 9.7 days, and mean final VA improved to 0.71 ± 0.32. Mean CCET at one month was 50.14 ± 5.33 µm, significantly thinner than in controls (59.79 ± 3.59 µm; p < 0.001). Central stromal thickness did not differ significantly between groups (p = 0.181). CCET showed no significant correlation with burn grade, initial VA, or epithelialization time (all p > 0.05). In an exploratory subgroup analysis, no significant difference in CCET was observed between patients receiving standard medical therapy alone and those requiring adjunctive treatment (p = 0.510); however, treatment allocation was non-randomized and reflected disease severity.

CCET is significantly reduced during early recovery after chemical burns despite apparent clinical healing. AS-OCT-based CCET measurement may provide an objective structural assessment of early epithelial changes during ocular surface healing.

What is known: 1) Chemical ocular burns cause severe disruption of the corneal epithelium and limbal stem cell function, and clinical epithelialization can not always reflect complete microstructural recovery. 2) Anterior segment OCT allows non-invasive assessment of corneal epithelial thickness, which has been shown to be reduced in several ocular surface disorders.

1) Although epithelial healing appears clinically complete in the early period after ocular chemical burns, AS-OCT demonstrated significant central corneal epithelial thinning despite a clinically stable ocular surface.