Late Recurrent Coats' Disease: Clinical Characteristics and Treatment Outcome

To investigate the clinical characteristics and outcomes of late recurrent Coats' disease after complete resolution.

Retrospective, comparative case-control study.

A total of 155 patients (155 eyes) with unilateral Coats' disease who achieved complete resolution after treatment and were followed for > 12 months thereafter. Patients were categorized into late recurrence (n=16) and long-term stable (n=139) groups.

Clinical records and multimodal ophthalmic imaging were reviewed. Late recurrence was defined as reappearance of abnormal vessels and exudations occurring >12 months after documented complete resolution.

Prevalence and time of late recurrence; baseline and recurrent clinical characteristics; treatment modalities; visual outcomes.

Late recurrence occurred in 10.3% of patients with a mean follow-up of 77.1 ± 37.8 months; mean recurrence-free interval was 53.4 ± 30.0 months (range, 15∼120 months). Recurrence rates varied by initial stage: 57.1% in stage 2A, 16.1% in stage 2B, 5.3% for stage 3A1, but none in stage 3A2, 3B and 4. The late recurrent group had a higher proportion of mild initial disease (87.5% vs 39.6%; P < 0.001), lower need for pars plana vitrectomy (PPV) (0% vs 46.8%, P < 0.001), and fewer quadrants of retinal damage after resolution (2.3 ± 1.0 vs 3.1 ± 1.0, P = 0.003) than the long-term stable group. All late recurrent patients received laser photocoagulation initially (100%), and 75% had visual improvement. Recurrent lesions were predominantly within the original abnormal area (87.5%), often manifesting as aneurysmal dilation (71.4%). Most recurrences (68.8%) were asymptomatic, detected on routine follow-up, and managed effectively with laser therapy to preserve visual function. In contrast, symptomatic patients (31.2%) presented with more advanced retinopathy, with widespread capillary leakage on fluorescein angiography (FA) beyond the zones of telangiectasia and exudation, and required more aggressive treatment (multiple laser sessions, intravitreal injections, or PPV).

Late recurrence of Coats' disease can occur years after complete resolution, particularly in eyes with milder initial presentation, less aggressive primary treatment, less post-treatment retinal damage and better baseline visual acuity. Since most recurrences were asymptomatic, long-term follow-up is crucial for early detection and preventing severe retinopathy.