Treatment of Intravitreal Ranibizumab Resistant Radiation Retinopathy with Intravitreal Dexamethasone Implant: A Case Report.

A 43-year-old female patient presented with complaints of decreased vision in both eyes. Her medical history revealed the diagnosis of metastatic breast cancer. She was treated with chemotherapy, and whole-brain, manubrium sterni, and right chest wall radiation therapy. Best-corrected visual acuity (BCVA) was 20/200 and 20/160 in the right and left eye, respectively. Optical coherence tomography (OCT) confirmed the presence of cystoid macular edema (CME). OCT angiography confirmed the presence of microaneurysms, ischemia, and capillary drop-out on the macula. Fundus fluorescein angiography revealed multiple microaneurysms with surrounding ischemia and leakage. Based on these findings and medical history, a diagnosis of radiation maculopathy was considered. The patient was administered intravitreal four doses of ranibizumab injections. Laser photocoagulation was performed on the ischemic areas of the retina in both eyes. Despite the follow-up and treatment, the presence of residual CME and BCVA 20/200 in both eyes was determined; it was decided to change the treatment regimen to an intravitreal dexamethasone implant. One month after injection, BCVA was 20/80 in both eyes, and normal foveal contour and no edema as confirmed on OCT. The DEX implant showed a promising result and should be kept in mind in the treatment of radiation retinopathy.