Cephalic radiation and retinal vasculopathy.

The retinal vascular complications in patients receiving cephalic radiation for various lesions over a ten year period were reviewed. The incidence of retinopathy was 17% overall, but increased with proximity of the treatment site to the eye, being highest in irradiation of the eye/orbit (85.7%), paranasal sinuses (45.4%) and nasopharynx (36.4%). The risk of retinopathy increased significantly when the total dose of radiation exceeded 3000 cGy. The occlusive vasculopathy and capillary incompetence which were the most clinically important features of radiation retinopathy may be exacerbated by pre-existing diabetes. Radiation retinopathy has a long latency and may not be clinically detectable for eight years or more. Long follow-up times with sequential fundoscopy should increase early detection and optimise treatment with laser photocoagulation.