Refining Coats' disease by ultra-widefield imaging and optical coherence tomography angiography

The purpose of our study was to describe ultra-widefield (UWF) imaging and optical coherence tomography angiography (OCT-A) findings in affected and fellow eyes of patients with Coats' disease. Consecutive patients affected by Coats' disease were prospectively recruited at the Department of Ophthalmology, San Raffaele Hospital, Milan, Italy in this cross-sectional, observational study. Patients underwent UWF color fundus photographs, UWF green autofluorescence, UWF fluorescein angiography (FA), optical coherence tomography (OCT), with 3 x 3 mm and 6 x 6 mm OCT-A scans of the macula. Images were qualitatively evaluated by two independent operators for the presence of pathology. Eleven patients affected by Coats' disease (eight males, mean age 17.1 +/- 6.7 years). Nine and two patients had a clinical diagnosis of unilateral and bilateral disease, respectively. Five eyes had macular fibrosis. All clinically affected eyes exhibited retinal pathology at UWF imaging with the temporal sector most involved followed by the inferior, nasal, superior and macula. In all eyes with macular fibrosis, OCT-A revealed replacement of the foveal avascular zone with coarse vessels suggestive of vascularized fibrosis and flow void area in the choriocapillaris due to a masking effect; type 3 neovascularization was seen in 75% of cases. Seven out of nine clinically unaffected fellow eyes showed retinal pathology at UWF FA with the temporal quadrant most involved. We demonstrated that Coats' disease is a highly asymmetric bilateral disease and that UWF imaging is able to identify more retinal pathology than standard fundus imaging, thus guiding proper retinal photocoagulation. OCT-A allowed easy identification of type 3 neovascularization in a proportion of patients with macular fibrosis.