Correlation of Outer Retinal Tubulations and Choriocapillaris Flow Signal Deficits surrounding Geographic Atrophy.

Purpose To evaluate and compare para- and perilesional choriocapillaris vascular impairment in eyes with geographic atrophy (GA) with and without outer retinal tubulations (ORT). Methods Using swept source optical coherence tomography angiography (OCTA), 6x6mm scans of eyes with GA with and without ORT were acquired. Choriocapillaris en face flow and structural images were binarized, prior to flow signal deficit (FD) analysis in the para-atrophy zone (a 500 µm wide band adjacent to the GA) and the peri-atrophy zone (a 500 µm wide band adjacent to the latter). Results Twenty-four eyes of 19 patients with ORT and 18 eyes of 15 patients without ORT were analyzed. With and without ORT, mean percental area of FD (%FD) was greater in para- than in peri-atrophy zone. The difference of %FD between para- and peri-atrophy zone (deltaFD) was lower in eyes with ORT (mean 1.8477%, 95% CI 0.8607 to 2.8346) than without ORT (mean 4.0018%, 95% CI 2.8622 to 5.1414). Conclusion In eyes with GA due to non-neovascular AMD, smaller reductions in FDs were found between the para- and peri-atrophy zone in eyes with ORT. In both cohorts, the para-atrophy zone had more FD than the peri-atrophy zone.