Evaluation of Automated Measurement of Macular Ischemic Changes in Retinal Vein Occlusion With Optical Coherence Tomography Angiography

OBJECTIVE: The foveal avascular zone (FAZ) is al-tered in patients with retinal vein occlusion (RVO) and correlates inversely with visual acuity. Opti-cal coherence tomography angiography (OCTA) is an imaging tool to visualize FAZ safely and easily. Automated measurements can facilitate interpre-tation of OCTA images. In this comparative cross-sectional study, we compare the results of manual measurement of the FAZ with automated measure-ment by built-in application (Metrix).METHODS: The study included patients with RVO who underwent OCTA. Manual measurement was compared with automated evaluation by Metrix in 3 mm x 3 mm and 6 mm x 6 mm scan sizes and cor-relations of the circularity, circumference, and size of the FAZ were calculated.RESULTS: Forty-seven eyes were included in the study. A reliable measurement result in both Metrix 3 mm x 3 mm and 6 mm x 6 mm was found in only 25 of 47 eyes. The mean FAZ in these eyes by manual measurement was 0.50 mm2 compared with 0.20 mm2 and 0.24 mm2, respectively, by automated measurement. A statistically signifi cant inverse cor-relation was found in both the automated 3 mm x 3 mm and 6 mm x 6 mm measurements for FAZ cir-cumference with FAZ circularity but not FAZ area.CONCLUSION: The two automated measurements showed no signifi cant bias regarding the size of the FAZ, but the plausibility of the data should be checked on a case-by-case basis. The manual mea-surements were higher, indicating limited agree-ment of manual and automated measurements. The information on circularity can point to ischemic maculopathy early in the course of the disease.