LAUSR

The arteriolar tortuosity index is significantly increased in COL4A1/A2 mutated patients, offering an accurate diagnostic approach in adults with cerebral microangiopathy. Purpose: Qualitative and quantitative analyses of retinal arteriolar tortuosity in patients with COL4A1 and COL4A2 mutations to identify a tortuosity index (TI) threshold for detecting increased retinal arteriolar tortuosity. Methods: Fifty-two eyes of 28 patients were included. Group 1 included eyes with a normal arteriolar pattern (n = 19, 37%), Group 2 included eyes with moderately increased arteriolar tortuosity (n = 13, 25%), and Group 3 included eyes with typical abnormal arteriolar tortuosity (n = 20, 38%). The TI was measured by calculating the arc-to-chord ratio of arterioles and venules in the posterior pole. Results: The mean arteriolar TI was significantly higher in all groups with a COL4A1/A2 mutation compared with controls: 1.19 ± 0.03, 1.24 ± 0.05, and 1.57 ± 0.23 in Groups 1, 2 and 3, respectively, versus 1.12 ± 0.01 (all P < 0.0001). The TI threshold was 1.13, with a sensitivity of 98.1% and a specificity of 100%. The area under the curve was 0.995. Conclusion: Measuring the arteriolar TI allowed diagnosing increased retinal arteriolar tortuosity in all eyes with a COL4A1/A2 mutation, whereas the subjective assessment suspected or detected it in only 62% of eyes. In adult patients with cerebral microangiopathy, detecting increased retinal arteriolar tortuosity, even when mild, directs the diagnosis toward COL4A1/A2-related cerebroretinal angiopathy.