PAMM and the ischemic cascade associated with radiation retinopathy

Purpose To report a case of paracentral acute middle maculopathy (PAMM) and evidence of the ischemic cascade documented with spectral domain optical coherence tomography (SD-OCT) following radiation treatment of a choroidal melanoma. Observations A healthy young patient was evaluated for an asymptomatic choroidal nevus in the left eye. Fundus examination was remarkable for a choroidal melanocytic lesion that measured 1.8 mm in thickness by initial B-scan ultrasound. Clinical examination 6 months later showed growth of the tumor at several margins with new subretinal fluid, and a B-scan measured thickness of 1.9 mm. The lesion was diagnosed as a small choroidal melanoma and treated with gamma knife radiation with a dose of 3000 cGy. Sixteen months later, examination showed signs of radiation retinopathy including cotton wool spots and PAMM via SD-OCT and OCT angiography and evidence of the ischemic cascade i.e. alternating zones of middle and combined middle and inner retinal layer infarction. Conclusions and Importance: Radiation retinopathy can include signs of microvascular damage and ischemia including lesions such as cotton wool spots and PAMM. A case is presented in this report of radiation retinopathy with OCT evidence of PAMM and the ischemic cascade.