Corneal Changes Assessed By Anterior Segment Optical Coherence Tomography During Hyperbaric Oxygen Therapy

To evaluate corneal structural changes using Anterior Segment Optical Coherence Tomography (AS-OCT) in eyes without pre-existing ocular disease undergoing repeated Hyperbaric Oxygen Therapy (HBOT) and to compare AS-OCT pachymetry with optical biometry measurements.

Ophthalmology Department and Hyperbaric Medicine Unit, Military Hospital of Tunis, Tunisia.

Seventy-four patients (148 eyes) scheduled for ≥30 HBOT sessions (2.5 ATA, 90 minutes, 5 sessions/week) were prospectively included. Central corneal assessment relied on multimodal pachymetry measurements using optical biometry (CCTb) and AS-OCT (CCT-AS). Evaluations were performed in both eyes at baseline (S0), every 10 sessions up to 60 sessions, and 3 months after treatment cessation.

Baseline mean CCT was 508±29 μm (RE) and 505±35 μm (LE). No significant variation was observed up to S20 (p=NS). From S30 onward, a mild but statistically significant corneal thinning was detected on both optical biometry and AS-OCT, reaching a maximum at S60 (mean decrease 5–8 μm; p<0.05). The reduction remained within physiological limits and was not associated with visual acuity loss. At 3-month follow-up, corneal thickness values returned to baseline with no significant difference compared to pre-treatment measurements (p=NS). AS-OCT and optical biometry showed excellent agreement and high reproducibility (ICC=0.92).

Anterior segment OCT demonstrates that repeated HBOT induces a mild, cumulative, and fully reversible decrease in central corneal thickness without clinically significant corneal structural damage. AS-OCT appears to be a sensitive tool for detecting subtle hyperoxia-related corneal microstructural changes during prolonged HBOT.