Radiation Retinopathy: Pathogenesis, Diagnosis, and Treatment

Radiation retinopathy is chronic retinopathy that usually after radiotherapy with delayed onset (6 months-3 years) and slow progression. The primary vascular event is endothelial cell loss. Clinically affected individuals may be asymptomatic or may describe decreased visual acuity. Combining anamnesis, complete ophthalmologic examination, and multimodal imaging is essential for diagnosis. The ophthalmological examination may reveal signs of retinal vascular disease such as microaneurysms (the first structural change detected ophthalmoscopically), cotton wool spots, retinal hemorrhages, perivascular sheathing, capillary telangiectasia, macular edema, and optic nerve head edema. Optical coherence tomography can detect macular edema, intraretinal hyperreflective spots that may develop secondary to ischemia, disorganization in the inner retinal layers, and deterioration in the outer retina. Fundus fluorescein angiography helps detect capillary perfusion anomalies and other signs of vascular disease. Diabetic retinopathy, retinal vein occlusion, ocular ischemic syndrome, hypertensive retinopathy, Coats' disease, and parafoveal telangiectasia should be considered in the differential diagnosis, and sometimes these diseases may accompany radiation retinopathy. Currently, there is still no standard treatment for radiation retinopathy. Anti-vascular endothelial growth factors (anti-VEGF) and steroid therapy are among the effective treatment options. Retinal laser photocoagulation can be applied for neovascular complications. For macular edema, focal laser photocoagulation was less effective than anti-VEGF and steroid therapy in terms of functional gain.