To evaluate the ability of optical coherence tomography angiography (OCTA) to quantitatively assess the effectiveness of intra‐arterial thrombolysis (IAT) surgery for the treatment of retinal artery occlusion (RAO).

This was a prospective observational study. Patients diagnosed with RAO who received IAT were enrolled. All participants underwent comprehensive ophthalmologic examinations and OCTA scans. The best‐corrected visual acuity (BCVA), vascular densities (VDs) of the superficial capillary plexus (SCP), deep capillary plexus (DCP), radial peripapillary capillaries, and central retinal thickness (CRT) were recorded. The above parameters were compared between RAO eyes and the fellow healthy eyes before and after IAT. Correlations between the BCVA and OCTA parameters in RAO eyes were calculated.

Thirty‐four eyes from 34 consecutive RAO patients with a mean age of 51.0 ± 12.9 years were enrolled. There was a considerable decrease of VDs in the SCP, DCP, and radial peripapillary capillaries in all RAO eyes (all p < 0.001). Compared with contralateral normal eyes, CRT was significantly increased in RAO eyes (p < 0.001). The SCP and DCP VDs were significantly improved after IAT surgery (p = 0.010 and 0.014, respectively). BCVA in logMAR unit was negatively correlated with the DCP VD (r = −0.664, p = 0.010) and positively correlated with CRT (r = 0.597, p = 0.024) after surgery, but not significantly correlated with VDs or CRT before surgery.

Macular and peripapillary VDs of the retina detected by OCTA were greatly decreased in RAO eyes and improved after IAT treatment. OCTA is capable of quantifying VDs in separate retinal layers non‐invasively, conveniently, efficiently, and precisely.