Up to ten years of visual acuity outcomes in fellow eyes post-uveal melanoma treatment with iodine-125 radiotherapy, transpupillary thermotherapy, and proton beam therapy.

Purpose: This study aimed to assess long-term visual acuity outcomes and multiple secondary factors in fellow eyes of uveal melanoma patients treated with either iodine-125 (¹²⁵I) plaque radiotherapy (PRT), transpupillary thermotherapy (TTT), or proton beam therapy (PBT).

Material and methods: A retrospective chart review of 213 patients treated from 2000 to 2022 was performed, with baseline and post-treatment visual acuity data collected at follow-up time points up to 10 years, when available. Paired t-tests compared changes in visual acuity (VA) and intraocular pressure (IOP) over time for affected and fellow eyes. Spearman's rho test assessed correlations between melanoma thickness and VA over time, and repeated measures ANOVA determined interactions between time and comorbidities in VA.

Results: Fellow eyes VA showed no significant change up to a decade post-treatment regardless of treatment modality, except for a likely false positive improvement at 2 years post-PRT. In contrast, affected eyes had significant VA decline post-PRT and PBT, while TTT used in affected eyes demonstrated no significant change. IOP did not show any significant changes in fellow eyes. Tumor thickness and the presence of diabetes, hypertension, or coronary artery disease, did not correlate with fellow eye VA outcomes.

Conclusions: This study suggests that following uveal melanoma treatment with either ¹²⁵I PRT, TTT, or PBT, fellow eyes remain stable regarding VA and other outcomes up to 10 years. This provides important information for treatment choice in patients with ocular melanoma, especially as VA can decline in affected eye post-treatment, leading to reliance on contralateral eye.