Incidence and Clinical Features of Neovascularization of the Iris following Acute Central Retinal Artery Occlusion

PURPOSE: To investigate the incidence of neovascularization of the iris (NVI) and clinical features of patients with NVI following acute central retinal artery occlusion (CRAO). METHODS: A retrospective review of 214 consecutive CRAO patients who visited one tertiary hospital between January 2009 and January 2015 was conducted. In total, 110 patients were eligible for this study after excluding patients with arteritic CRAO, a lack of follow-up, iatrogenic CRAO secondary to cosmetic filler injection, or NVI detected before CRAO attack. Fluorescein angiography (FA) was applied until retinal arterial reperfusion was achieved, typically within 1 to 3 months. RESULTS: The incidence of NVI was 10.9% (12 out of 110 patients). Neovascular glaucoma was found in seven patients (6.4%). The mean time to NVI diagnosis after CRAO events was 3.0 months (range, 1 week to 15 months). The cumulative incidence was 5.5% at 3 months, 7.3% at 6 months, and 10.9% at 15 months. Severely narrowed ipsilateral carotid arteries were observed in only three patients (27.3%). The other nine patients (75.0%) showed no predisposing conditions for NVI, such as proliferative diabetic retinopathy or central retinal vein occlusion. Reperfusion rate and prevalence of diabetes were significantly different between patients with NVI and patients without NVI (reperfusion: 0% [NVI] vs. 94.7% [no NVI], p < 0.001; diabetes: 50.0% [NVI] vs. 17.3% [no NVI], p = 0.017). CONCLUSIONS: CRAO may lead to NVI and neovascular glaucoma caused by chronic retinal ischemia from reperfusion failure. Our results indicate that follow-up fluorescein angiography is important to evaluate retinal artery reperfusion after acute CRAO events, and that prophylactic treatment such as panretinal photocoagulation should be considered if retinal arterial perfusion is not recovered.