Vascular findings in primarily affected and fellow eyes of middle-aged patients with Coats' disease using multimodal imaging.

Aims: To investigate the retinal vascular structure and capillary anomalies of affected and fellow eyes of patients with unilateral Coats' disease using multimodal imaging.
Methods: Clinical investigation of both eyes of each patient with diagnosed Coats' disease using ultra-widefield (UWF) fundus imaging, including UWF fluorescein angiography (UWFFA), spectral domain optical coherence tomography (OCT) and optical coherence tomography angiography (OCT-A).
Results: We analysed 38 eyes of 19 patients with unilateral Coats' disease and found that all fellow eyes (19/19; 100%) revealed vascular alterations, detected by UWFFA, predominantly located in the temporal periphery. Thereby, 89% of the fellow eyes (17/19) presented capillary bed abnormalities, that did not exceed the capillary level; 58% (11/19) presented tortuous abnormalities and 26% (5/19) presented microaneurysmatic abnormalities, exceeding the capillary level. If primarily affected eyes presented central Coats' specific vascular abnormalities, fellow eyes revealed tortuous vascular abnormalities twice as often (78% (7/9) vs 40% (4/10); P=0.096). In primarily affected eyes, a tendency towards larger foveal avascular zones was revealed, compared to fellow eyes (0.28±0.16 mm ² vs 0.20±0.10 mm ² ; P=0.123).
Conclusion: The use of modern multimodal imaging allows the detection of even subtle vascular changes in fellow eyes of patients with Coats' disease. Coats' disease appears to be a bilateral ocular disease with a predominant manifestation in one eye of the affected patients.
Competing Interests: Competing interests: None declared.
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