Optical coherence tomography angiography findings in patients with acute nonarteritic central retinal artery occlusion treated with carbogen inhalation

Central retinal artery occlusion (CRAO), a retinal vascular disease that causes severe vision loss, can be evaluated by noninvasive modalities such as optical coherence tomography angiography (OCTA). However, no longitudinal quantitative studies have assessed OCTA in eyes with CRAO treated with carbogen inhalation. In this prospective, observational study, we evaluated the parametric changes of OCTA in patients with acute nonarteritic CRAO treated with carbogen inhalation. Best-corrected visual acuity and all OCTA parameters in eyes with acute nonarteritic CRAO were obtained before initiating carbogen inhalation, 12 to 24 hours and 36 to 48 hours after, and at 1 to 2 weeks and 4 to 6 weeks of follow-up. Twenty-five CRAO eyes were included. The initial OCTA showed reduced vessel density (VD) in both the superficial and deep capillary plexus in the whole-image area, parafovea, and perifovea, which remained decreased until 4 to 6 weeks. The VD at the fovea initially increased, followed by a reduction at 1 to 2 weeks and 4 to 6 weeks. Retinal edema was universal and improved at 1 to 2 weeks and 4 to 6 weeks. No VD recovery was observed after carbogen inhalation. Eyes with acute nonarteritic CRAO showed VD reduction, except at the fovea. No VD recovery was observed after carbogen inhalation. Baseline OCTA parameters did not predict favorable visual outcomes.