ASYMMETRY OF DISCIFORM SCARRING IN BILATERAL DISEASE WHEN ONE EYE IS TREATED WITH RADIOTHERAPY

Aims/Background-A previous study has shown that in age-related macular degeneration a high degree of concordance of disciform scar size occu rs in the two eyes of any one patient. In a study of 35 patients with choroidal neovascular membrane who were treated with low dose ionising radiation to the macula of the affected eye, 11 were found to have bi lateral disease. Methods-The visual outcome and scar size and morpholo gy in the two eyes of each of these patients were compared. Results-In all radiotherapy treated eyes the appearance of the scar ranged from subtle subretinal pigmentary changes to dense subretinal fibrosis. By contrast all untreated fellow eyes showed marked subretinal scarring. Scars in radiotherapy treated eyes occupied an area that was approxima tely one third of that in untreated fellow eyes (3.8 mm(2) v 11.7 mm(2 )). Distance and near visual acuities in radiotherapy treated eyes wer e significantly better than that of untreated fellow eyes (p<0.0033). Although untreated fellow eyes of necessity had longer follow up perio ds (64.5 months), the mean follow up time in treated eyes was 28 month s by which time the disciform response is generally thought to have ce ased evolving. Conclusion-This study has provided evidence in support of reduced scarring and maintenance of better central visual function in radiotherapy treated eyes when compared with untreated fellow eyes.