VISUAL-FIELD DEFICITS ASSOCIATED WITH PROTON-BEAM IRRADIATION FOR PARAPAPILLARY CHOROIDAL MELANOMA

Purpose: A large series of patients treated with proton irradiation fo r parapapillary choroidal melanoma were reviewed retrospectively to de termine the frequency of radiation papillopathy and visual-field loss after treatment. Methods: Among 249 patients treated with proton irrad iation for parapapillary choroidal melanoma, the authors identified 59 patients who had visual-field testing performed before treatment and at least 18 months after treatment, The visual fields, color fundus ph otographs, and charts were reviewed to determine the prevalence of rad iation papillopathy and visual-field loss after treatment. Results: Ni neteen of the 59 patients reviewed (31%) received a clinical diagnosis of radiation papillopathy, Progressive visual-field loss, defined as enlargement of absolute scotoma of less than or equal to 30 degrees as compared with the pretreatment visual field, was noted in 67% of pati ents with radiation papillopathy and 73% of patients without papillopa thy. In both groups, visual-field loss correlated with the area of the retina predicted to be exposed to irradiation in the majority of pati ents. Conclusions: Progressive visual-field loss is common after proto n irradiation for parapapillary choroidal melanoma. However, the scoto ma usually correlates with the area of the retina exposed to irradiati on. The development of radiation papillopathy does not appear to be as sociated with additional visual-field defects in most cases.