External radiotherapy in macular degeneration: technique and preliminary subjective response

This study was to assess the toxicity and possible preliminary benefits from the administration of low dose external beam irradiation for Age Related Macular Degeneration (ARMD). The main goal of using radiation is to induce regression and/or promote inactivation of the subretinal neo-vessels which would result in reabsorption of fluid and blood. This would reduce the risk for further leakage or bleeding as well as subretinal fibrosis. Consequently the beneficial effect could be translated into stabilization of visual acuity and prevention of progression of the wet ARMD with the possibility for slight improvement. Hahnemann University Department of Radiation Oncology treated 41 patients prospectively from January through October 1995 with low dose irradiation for wet type macular degeneration. Thirty-nine patients were treated with a total dose of 1440 cGy in 8 fractions of 180 cGy per fraction over 10-13 elapsed days. The first 2 patients were treated to a total dose of 1000 cGy in 5 fractions of 200 cGy. Patients were evaluated at 2-3 weeks and 2-3 months. Some of the patients (36.7%) had laser treatments in the eye study, 21.9% (9) once, 5% (2) twice, 9.7% (4) three or more. Subjective visual acuity and toxicity data were collected on all patients. At 2-3 weeks after treatment 29 patients (70%) retained their visual acuity without change, 10 patients (24.5%) stated they had improved vision and 2 patients (4.8%) stated their vision continued to decrease. Two to three months after treatment 27 patients (65.8%) had no change in their vision, 11 patients had an improvement in their vision, and 3 patients (7.2%) had a decrease in visual acuity. There were 6 patients out of the 41 treated group that had acute and transient side effects. Our observations in this group of 41 patients supports the conclusion that many patients will have improved or stable vision after treatment with low dose irradiation for age related wet type macular degeneration