To investigate features and outcomes of Coats disease by patient age.

Patients with Coats disease from 1973 to 2018 were evaluated based on age category at presentation (3 years or younger vs older than 3 to 10 years vs older than 10 years).

There were 351 eyes of 351 patients with Coats disease diagnosed (2 vs 6 vs 27 years, P < .001). The youngest age group had more referral diagnoses of retinoblastoma (29% vs 15% vs 0%, P < .001), worse presenting visual acuity (< 20/200: 80% vs 67% vs 31%, P < .001), more advanced Coats disease stage (stage 3B: 65% vs 38% vs 10%, P < .001), and greater clock-hour extent of telangiectasia (7 vs 5 vs 4, P < .001), light bulb aneurysms (7 vs 4 vs 3, P < .001), exudation (10 vs 7 vs 5, P < .001), and subretinal fluid (10 vs 7 vs 4, P < .001). The oldest patients received a greater total number of treatments (3.3 vs 3.1 vs 4.4, P = .04), with more argon laser photocoagulation (37% vs 52% vs 73%, P < .001) and intravitreal anti-vascular endothelial growth factor (6% vs 9% vs 23%, P < .002) and less cryotherapy (74% vs 84% vs 58%, P < .001). At mean follow-up (70 vs 65 vs 38 months, P = .02), the youngest patients had poorer visual acuity outcome (< 20/200: 83% vs 64% vs 39%, P < .001), had less disease resolution (43% vs 65% vs 62%, P = .01), and were more likely to ultimately require enucleation (22% vs 10% vs 6%, P = .01).

Younger patients (3 years or younger) with Coats disease present with worse visual acuity and more advanced disease stage, and are more likely to require ultimate enucleation.