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

Purpose: 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. Methods: 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. Results: 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 mm) were significantly higher than with OCTA without EFI (40.40 ± 34.87 and 24.26 ± 21.82 mm, P < 0.001) but lower than with FA/ICGA 102° (140.7 ± 69.23 and 108.3 ± 69.51 mm, 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 mm). 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. Conclusion: 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.