# Impact of a single session of hyperbaric oxygen therapy on the healthy retina

## TL;DR

A single session of hyperbaric oxygen therapy caused temporary changes in retinal function and structure in healthy eyes.

## Contribution

This study is the first to show acute retinal effects of a single HBOT session using ffERG and SD-OCT in healthy individuals.

## Key findings

- Scotopic 0.01 ERG b-wave amplitude decreased significantly after HBOT.
- Retinal pigment epithelium thickened in the nasal subfield after HBOT.

## Abstract

Hyperoxia induced by hyperbaric oxygen therapy (HBOT) may lead to retinal vasoconstriction and the generation of reactive oxygen species. This study aims to investigate the effects of a single session of HBOT on the healthy retina using full-field electroretinography (ffERG) and spectral-domain optical coherence tomography (SD-OCT).

Twenty patients diagnosed with either sensorineural hearing loss or avascular necrosis, all of whom had an indication for HBOT, were included in the study. A comprehensive ophthalmologic examination, along with ffERG and SD-OCT assessments of the retinal layers and choroid, were performed both before and within 24 hours after the first HBOT session.

The mean age of the participants was 43.2 ± 11.4 years (range, 18–66 years). A statistically significant difference was observed only in the scotopic 0.01 ERG b-wave amplitude before and after HBOT (p = 0.029). The retinal pigment epithelium in the 3-mm nasal subfield of the Early Treatment Diabetic Retinopathy Study (ETDRS) grid demonstrated a statistically significant thickening after the first HBOT session (p = 0.023).

A single session of HBOT induced an acute alteration in rod–bipolar cell function, as evidenced by impaired electrophysiological responses. Additional studies are necessary to clarify the duration and potential reversibility of the observed electrophysiological impairment.