Acute Effect of Hyperbaric Oxygen Therapy on Corneal Parameters

Abstract Aim: The aim of this study was to evaluate the effect of hyperbaric oxygen therapy (HBOT) on central corneal thickness (CCT) and corneal endothelial cell density (ECD) in patients undergoing treatment for various systemic conditions. Materials and Methods: This observational study was conducted at a tertiary care center and included a total of 50 patients (100 eyes) receiving HBOT. Inclusion criteria comprised patients aged ≥25 years undergoing HBOT for non ocular systemic indications, with clear corneas, normal baseline endothelial morphology, and no history of prior ocular surgery or corneal pathology. Patients with glaucoma, active ocular infection, corneal dystrophies, contact lens use, and history of prior ocular surgery, including cataract surgery, vitreoretinal surgery, or keratorefractive procedures were excluded. Each participant underwent a comprehensive ophthalmic evaluation. Intraocular pressure (IOP), central corneal thickness, and endothelial cell density were measured immediately before and within 1 hour after a single HBOT session. The HBOT protocol consisted of administration of 100% oxygen at 2.5 atmospheres absolute (ATA) for 90 minutes. Measurements were obtained using standardized non-contact pachymetry and specular microscopy. Statistical analysis was performed using a paired t -test to compare pre- and post-treatment values, with significance set at p < 0.05. Results: A total of 100 eyes from 50 patients were analyzed, including 66% males and 34% females. The mean central corneal thickness decreased from 530.34 ± 40.4 μm pre-HBOT to 520.90 ± 41.5 μm post-HBOT, showing a statistically significant reduction. The mean endothelial cell density showed a slight increase from 2647.81 ± 244.45 cells/mm 2 to 2661.91 ± 220.58 cells/mm 2 , which was not clinically significant. Conclusion: A single session of HBOT induces statistically significant but transient changes in central corneal thickness and intraocular pressure, without adversely affecting corneal endothelial cell density in eyes with healthy endothelium. These findings suggest that short-term HBOT is safe for corneal endothelial integrity in the general population.