EXTENDED FIELD IMAGING OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY FOR THE STUDY OF RETINAL AND CHOROIDAL CHANGES AFTER RADIATION THERAPY FOR CHOROIDAL MELANOMA: Comparison With Wide-Field Angiography.

Abstract

Radiation retinopathy is a common side effect of ocular radiotherapy with no long-term effective therapy. Optical coherence tomography angiography (OCTA) and wide-field fluorescein angiography (FA) are widely used for the study of radiation maculopathy and peripheral nonperfusion, respectively. We investigated the role of extended field imaging (EFI-OCTA) for the study of retinal and choroidal alterations after radiotherapy for choroidal melanoma. Cross-sectional observational study of 20 eyes of 20 patients diagnosed with radiation retinopathy. All patients underwent a complete imaging evaluation including FA and indocyanine green angiography (ICGA) with 55° and 102° lens (Spectralis Heidelberg Engineering, Heidelberg, Germany). Optical coherence tomography angiography imaging was performed with the Zeiss PlexElite 9000 Swept Source OCTA (Carl Zeiss Meditec, Dublin, CA) using a 12 × 12-mm volume scan pattern centered on the fovea and a +20.00-diopter lens specifically designed to obtain EFI examination. The imaging methods were then compared in terms of visible field of view, extension of nonperfused areas, and vessel density. The mean extension ratio of EFI-OCTA compared to OCTA without EFI, FA/ICGA 55° and FA/ICGA 102° was, respectively, 1.98 ± 0.02, 1.21 ± 0.01 and 0.36 ± 0.003. The mean extension of retinal and choroidal nonperfused areas evaluated by EFI-OCTA (63.03 ± 48.21 and 38.63 ± 30.83 mm2) were significantly higher than with OCTA without EFI (40.40 ± 34.87 and 24.26 ± 21.82 mm2, P < 0.001) but lower than with FA/ICGA 102° (140.7 ± 69.23 and 108.3 ± 69.51 mm2, P < 0.001). No significant differences were found between mean extension of retinal and choroidal ischemic areas measured with EFI-OCTA and FA/ICGA 55° (69.64 ± 51.92 and 47.23 ± 33.59 mm2). The mean vessel density of EFI-OCTA (retina and choroid segmentation) was significantly different compared to OCTA without EFI (P < 0.05). Retinal vessel density was negatively correlated to retinal extension of nonperfused areas (r = -0.5, P = 0.02), and choroidal vessel density was negatively correlated to choroidal nonperfused areas (r = -0.6, P = 0.003) measured with EFI-OCTA. In our series, EFI-OCTA captured larger areas than OCTA without EFI and FA/ICGA with 55° lens. EFI-OCTA images showed a good definition of retinal and choroidal vascular changes after radiotherapy, suggesting a possible role of this safe and noninvasive imaging technique in the follow-up of patients with radiation retinopathy.