To compare hyperbaric oxygen treatment combined with hemodilution with hemodilution only in central retinal artery obstruction. Retrospective, nonrandomized case series. We reviewed records of all our patients diagnosed with central retinal artery obstruction between 1997 and 2010. In these patients, hyperbaric oxygen and hemodilution therapy had been administered routinely (oxygen group). Where hyperbaric oxygenation could not be performed, patients were underwent hemodilution only (control group). Patients with presenting visual acuity (VA) of up to 20/200 within 12 hours of onset were included in our analysis. Exclusion criteria included cilioretinal vessels or arteritic occlusion. The oxygen group comprised 51 patients, and the control group comprised 29 patients. Mean baseline VA was counting fingers (oxygen group) and 20/1000 (control group; P = .1). Most other potential confounders, including duration of symptoms, also did not differ significantly at baseline. In the oxygen group, mean VA improvement was 3 lines (P < .0001). This was sustained over a follow-up of 3 months (P = .01). In the control group, mean improvement was 1 line (P = .23 at discharge, P = .17 at follow-up). Differences between both groups were not significant (P = .07 at discharge, P = .26 at follow-up). The number of patients gaining 3 lines or more was 38.0% versus 17.9% at discharge (P = .06) and 35.7% versus 30.8% at follow-up (P = .76). Menzel-Severing, Siekmann, Weinberger, Roessler, Walter, Mazinani, , , (2012). Early hyperbaric oxygen treatment for nonarteritic central retinal artery obstruction. American journal of ophthalmology, 2012 Mar;153(3):454-459.e2. https://www.ncbi.nlm.nih.gov/pubmed/21996308