What Researchers Did
Researchers used optical coherence tomography to measure detailed eye structure changes in 42 healthy volunteers before and after a single session in a hyperbaric chamber pressurized to 2.4 ATA with normal (21%) oxygen, simulating what divers and submarine workers regularly experience.
What They Found
After one hyperbaric session, retinal nerve fiber layer thickness decreased in the central retina, the outer plexiform layer thickened, and retinal pigment epithelium thinned slightly in the mid-retina. Choroidal thickness increased significantly in the nasal, temporal, and average measurements. These changes are consistent with elevated intracranial perfusion pressure caused by increased venous pressure.
What This Means for Canadian Patients
This study is relevant primarily to Canadian divers, commercial marine workers, and others regularly exposed to high-pressure environments, not HBOT patients, since therapeutic HBOT uses oxygen, not air. The findings suggest that even normal-oxygen high-pressure environments cause measurable, though likely temporary, changes to eye structure.
Canadian Relevance
No direct Canadian connection identified. This study concerns occupational diving exposure, not therapeutic HBOT, and is not tied to any OHIP-covered indication.
Study Limitations
The study included only one measurement session with a short 30-minute post-exposure window, so it is unknown whether the structural changes are temporary or cumulative.