Thirty-year visual acuity outcomes after plaque brachytherapy for posterior uveal melanoma

OBJECTIVE: To quantify 30-year visual-acuity outcomes after ruthenium 106 or iodine 125 plaque brachytherapy for posterior uveal melanoma and identify independent predictors of best-corrected visual acuity (BCVA) <20/200. DESIGN: A retrospective single-centre cohort study. PARTICIPANTS: Participants were 1 785 consecutive patients treated at St. Erik Eye Hospital (Stockholm, Sweden) from 1979 to 2024 (median follow-up 12.4 years). METHODS: Visual-acuity survival was estimated using Kaplan-Meier curves. Cumulative-incidence functions and multivariable Fine-Gray competing-risk regression modelled the risk of acuity <20/200. A 3-level FIT (fovea-isotope-thickness) score was derived and validated to stratify eyes into low-, medium-, and high-risk groups. RESULTS: Mean visual acuity declined from 0.34 logMAR (20/44) at diagnosis to 0.82 logMAR (20/132) at the last follow-up. Probabilities of maintaining acuity ≥20/200 were 64% (95% CI: 61-66) at 5 years, 40% (95% CI: 37-44) at 10 years, 18% (95% CI: 14-23) at 20 years, and 4% (95% CI: 1-11) at 30 years. Among eyes beginning with ≥20/40, corresponding probabilities were 73%, 52%, 26%, and 8%. Iodine 125 plaques (sHR [subdistribution hazard ratio]: 3.57 vs ruthenium 106; 95% CI: 2.43-5.23) independently predicted vision <20/200, while each additional millimetre of tumour-fovea distance was protective (sHR 0.90; 95% CI: 0.86-0.95). Neither prescribed apex dose nor anti-vascular endothelial growth factor-era treatment was associated with BCVA prognosis. Ten-year incidences of BCVA <20/200 were 24%, 49%, and 77% in low-, medium-, and high-risk FIT categories. CONCLUSIONS: Three decades after plaque brachytherapy, fewer than 1 in 20 eyes retained useful vision. Iodine 125 plaques and tumours abutting the macula carried the greatest risk. The FIT score may assist clinicians in counselling and selecting sight-preserving strategies.