Acute Effect of Hyperbaric Oxygen Therapy on Macular and Choroidal Thickness in Patients with Type 2 Diabetes and Diabetic Foot Ulcers: Optical Coherence Tomography Based Study.

PURPOSE: To evaluate the acute effect of hyperbaric oxygen therapy (HBOT) on central macular thickness (CMT) and choroidal thickness (CT) in patients with type 2 diabetes mellitus (T2D) undergoing HBOT due to diabetic foot ulcer (DFU).

METHODS: For this cross-sectional study, patients with T2D were recruited between May 2019 and June 2020. Only eyes with non-proliferative or no diabetic retinopathy (DR) were included. CMT and subfoveal, nasal, and temporal CT values measured by spectral-domain optical coherence tomography (Nidek RS-3000 Advance, Aichi, Japan) before and 45 minutes after the first HBOT session were compared between eyes with and without DR and between patients receiving only insulin therapy (group 1) or insulin+oral antidiabetic (group 2). Relationships between post-HBOT change in these parameters and age, sex, HbA1c level, and DR presence and stage were evaluated.

RESULTS: The study included 49 eyes of 26 patients with DFU (aged 43-75 years). Post-HBOT changes in CMT and CT were not significant or associated with age, gender, DR stage, or HbA1c level (p>0.05). Eyes with DR had significantly higher pre- and post-HBOT CMT, nasal CT, and temporal CT values compared to non-DR eyes. Nasal CT increased significantly after HBOT in eyes with DR. Group 1 (28 eyes, 15 patients) had higher pre-HBOT mean subfoveal CT and greater post-HBOT change in subfoveal CT than group 2 (21 eyes, 11 patients).

CONCLUSIONS: HBOT was not associated with acute changes in CMT or CT in patients with T2D, although an increase in nasal CT was observed in eyes with DR.