Name

Analyse quantitative des altérations de la choriocapillaire, en OCT-Angiographie, au cours de la rétinopathie radique

To evaluate choriocapillaris alterations following proton beam therapy (PBT) irradiation using swept-source OCTA, and to assess their correlation with the grade of radiation retinopathy (RR).

Eyes with uveal melanoma (UM) irradiated or not with PBT were included, as well as the healthy fellow eye. The gradation of RR was based on a previously published classification. Choriocapillaris flow voids area was analyzed using Phansalkar thresholding. Retinal vascularization was described by foveal avascular zone (FAZ) perimeter, FAZ area, FAZ circularity index (CI), and percentage of non-perfusion area (PAN) in the superficial (SCP) or deep capillary plexus (DCP). 

A total of 157 eyes of 83 patients were analyzed. Overall, there was a significant difference between the control group, UM/without PBT group and the grades of RR in the UM/PBT group for FAZ perimeter (p<0.001), FAZ area (p<0.001), FAZ-CI (p<0.001), PAN-SCP (p<0.001), PAN-DCP (p<0.001) and choriocapillaris flow voids area (p<0.001). Moreover, choriocapillaris flow voids area was significantly increased in the early stages of RR (p=0.048) and was further significantly correlated with FAZ perimeter (p<0.001), FAZ area (p<0.001), FAZ-CI (p=0.010), PAN-SCP (p<0.001) and PAN-DCP (p<0.001).

In the present study, we showed that vascular alterations in the retina and choriocapillaris can be detected by OCTA after PBT for the treatment of UM. All the OCTA parameters analyzed, including choriocapillaris flow voids area, remained significantly different at some point along the evolution of the RR grade. Most importantly, we found that the choriocapillaris layer was altered at very early stages of RR,

Quantitative OCTA alterations in the choriocapillaris microvascularisation are an early biomarker of RR and are correlated to the severity of the disease.