OCT-angiography for the diagnosis of radiation maculopathy in patients treated with proton beam therapy: A 2-year prospective study

Abstract

Purpose Radiation maculopathy (RM) is the leading cause of visual acuity (VA) loss after proton beam therapy (PBT) of choroidal melanoma. The aim of this study was to assess the value of optical coherence tomography-angiography (OCT-A) for the diagnosis of RM in patients with choroidal melanoma treated with PBT. Materials & methods This 2-year prospective, descriptive, single-center study included patients treated with PBT for choroidal melanoma. VA measurement, retinography, OCT and OCT-A were performed. Vascular density (VD) in the superficial capillary plexus (SCP), peri-foveal anastomotic ring changes and foveal avascular zone (FAZ) enlargement were studied. Results Nineteen patients were included in the study. The median baseline melanoma thickness was 5.7 [3.6–8.1] mm. The median melanoma-to-macula distance was 3.5 [2.6–4.6] mm. The earliest signs of RM identified on retinography were hard exudates developing at 12 [12–24] months, followed by retinal hemorrhages at 18 [12–30] months, found in 88.9% and 77.8% of patients respectively. On OCT, the earliest sign was the onset/progression of cystoid macular edema (CME) at 12 [6–12] months, found in 10 patients (52.6%). On OCT-A, 100% of patients presented with a discontinuity of the perifoveal anastomotic ring and a FAZ enlargement after 12 [6–24] months. After 12 months, a VD loss in the SCP by 11.7% and 10.8% compared to baseline, was found in the macular and foveal areas respectively. A significant negative correlation was found between the VA and the VD in the macular SCP (R = −0.43; p = 0.029). Conclusion OCT-A is a reliable and effective diagnostic tool for RM in patients with choroidal melanoma treated with PBT.