Purpose: To assess morphologic characteristics of retinal arterial macroaneurysm (RAM) and their vascular changes using optical coherence tomography angiography (OCTA).
Methods: This observational study included 31 eyes of 29 participants diagnosed with RAM based on fundus fluorescein angiography in Tianjin Medical University Eye Hospital. Multimodal imaging modalities, including fundus photography, fluorescein angiography, and OCTA, were used to examine RAMs. The demographic and clinical characteristics of the RAMs were recorded.
Results: Depending on the fundus fluorescein angiography examination, 40 cases of RAM were confirmed in 29 patients. Twenty-three patients were female (79%), and six patients were male (21%). Two patients had binocular RAM, and four eyes had more than one RAMs. Relying on the OCTA technology, RAMs have four different vascular morphology types (i.e., distended, meshed, malformed, and occult types). In the distended type, round or encircled thrombi caused asymmetrical or symmetrical distention of retinal arteriolar, leading to separate true lumen and false thrombus lumen in RAM. In the meshed type, the meshed or dendritic vascular network around the RAM was likely to be the neovascularization due to the ischemia and hypoxia of the arteriolar wall. Finally, in the malformed and occult type, the RAM usually regressed, and the retinal arterioles were remodeled to distorted or normal arterioles accompanied by capillary degradation.
Conclusion: Relying on the OCTA technology, we found that the RAMs have four different types of vascular morphology. Each group of RAM has different vascular features. The application of OCTA in patients with RAM furthers our understanding of the vasculature of RAMs.