LOW-DOSE RADIATION ON THE SUBFOVEAL NEOVASCULAR MEMBRANES (SNVM) IN AGE-RELATED MACULAR DEGENERATION

Aim of the study The aim of this study is to test the effect of low dose radiation on the subfoveal neovascular membranes (SNVM) and to analyse visual acuity in age-related macular degeneration. Methods and patients From November 1993 through to August 1994, 10 patients,on the one hand, were given a dose of 5 Gy followed by controls 6 weeks and 6 months later. On the other hand, 21 patients were treated with a dose of 8 Gy and were subjected to controls 6 weeks later. Before the radiotherapy and during the control sessions, all patients were required to be measured for different parameters of visual acuity and to receive a simultaneous fluorescein and indocyanine green angiography. The radiotherapy was done by a linear accelerator 6 MeV and through a lateral port 3 x 4 cm in half beam technic. Results In the 5 Gy group, no changes in the parameters for visual acuity were noted in most cases after 6 months. In 9 of the cases, the membranes had increased in size and in 1 case, they had remained unchanged. In the 8 Gy group, no changes in the visual acuity or in the membrane size were diagnosed. Of all the patients treated, only one refused the angiography control. Discussion and conclusions Given the low dose used and the period of observation, the visual acuity of all patients remained stable. The size of the membranes increased in most cases for those 5 Gy patients and in this respect, no changes at all were noted in the 8 Gy patients. In order to better evaluate the potential of radiotherapy, this study must be pursued and coupled with further studies analysing the effect of different doses on patients.