Prognostic factors for acute central retinal artery occlusion treated with hyperbaric oxygen: The Hong Kong study report number five.

Background: Central retinal artery occlusion (CRAO) is a potentially blinding disease, and hyperbaric oxygen therapy (HBOT) is becoming increasingly popular with the support of scientific evidence. Despite the presence of various acute management measures, there is no clear evidence on the gold standard treatment for CRAO.

Aim: To identify factors and imaging parameters associated with good visual outcome, which guide ophthalmologists in the triage of CRAO patients for HBOT.

Methods: Patients who suffered from CRAO and had a symptom onset ≤ 6 h were recruited for a course of HBOT in a tertiary hospital after failing bedside treatment. Patient demographics, onset time, CRAO eye parameters, and past medical history were prospectively collected. Visual outcomes after HBOT were also analyzed.

Results: A total of 26 patients were included; the female-to-male ratio was 1:1.6, and the mean age was 67.5 years ± 13.3 years (range 44-89 years). The mean duration of follow-up and mean visual acuity (VA) improvement were 10.0 mo ± 5.3 mo and 0.48 logarithm of minimal angle of resolution (logMAR) ± 0.57 logMAR (approximately 9 letters in ETDRS) (P = 0.0001, Z = -3.67), respectively. The 1 mm zone of central macular thickness (CMT) on optical coherence tomography was not associated with VA changes (P = 0.119); however, the 1-to-3 mm circular rim of CMT was fairly associated (P = 0.02, Spearman's coefficient = 0.45). Complete retinal perfusion time during fundus fluorescein angiography (FFA) was moderately associated (P = 0.01, Spearman's coefficient = 0.58) with visual outcome.

Conclusion: A thinner 1-to-3 mm circular rim of CMT, but not the central 1 mm zone, is associated with better visual outcome. A shorter perfusion delay on FFA is also associated with better visual outcome.