Development of subfoveal nodule in Coats' disease: Prevalence, stages, prognosis, and treatment

To investigate the prevalence, developmental stages, and factors affecting the progression of subfoveal nodules (SFN) in Coats' disease.

A retrospective review of medical records and multimodal images was conducted for patients with Stage 2A-3A Coats' disease in a tertiary university setting. SFN development was classified into five stages: Stage 0 - macular exudation without subfoveal hard exudate; Stage 1 - subfoveal exudation; Stage 2 - consolidation of exudation; Stage 3- vascularization of SFN; Stage 4 - scarring and subfoveal fibrotic nodule. Factors influencing the formation and progression of SFN were analysed.

The study included 44 eyes of 43 patients, with a mean age of 6.9 ± 4.1 years and a mean follow-up of 33 months. SFN prevalence was 48% initially and 91% at final follow-up. No differences were noted in baseline demographics or clinical characteristics across SFN stages. Patients developing SFN earlier than 9 months were significantly younger than those developing in a longer period (>9 months) (5.9 ± 2.7 vs. 8.9 ± 3.6, p = 0.037), and the mean number of intravitreal (IV) anti-VEGF/steroid injections applied per year was lower in the latter group (3.69 ± 1.29 vs. 1.12 ± 1.21, p = 0.001). The risk of early SFN development was 2.4 times higher in patients under 7 years and four times higher in those receiving three or fewer IV anti-VEGF/steroid injections per year.

The prevalence of SFN (91%) in this study was found to be higher compared with the literature. More frequent anti-VEGF/steroid injections, compared with conventional treatment, may slow the progression of SFN.