PURPOSE: To determine vascular change at the macula in both eyes in unilateral pediatric Coats disease using optical coherence tomography angiography. METHODS: Retrospective case-series. Thirteen eyes of pediatric patients with a diagnosis of unilateral Coats disease of various stages were compared with 13 fellow eyes. Optical coherence tomography angiography images were acquired using the RTVue XR Avanti. Scans were analyzed with novel projection artifact removal software and improved segmentation. Vascular density and foveal avascular zone area were calculated. RESULTS: Vascular density was significantly decreased in eyes with Coats disease in comparison with fellow eyes in both the superficial capillary plexus and deep capillary plexus (43.7 ± 4.7 vs. 45.9 ± 4.4 [P = 0.000] and 43.0 ± 6.3 vs. 50.3 ± 2.2 [P = 0.001], respectively). The difference was also significant for most sectors of the macula. Foveal avascular zone area was significantly larger in eyes with Coats disease in comparison with fellow eyes (0.29 ± 0.1 vs. 0.24 ± 0.09 [P = 0.003]). These significant differences appeared as early as Stage 2A, preceding clinical findings. CONCLUSION: The findings support the unilaterality of Coats disease and show that vascular changes on optical coherence tomography angiography precede clinical staging of the condition.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal
