Optical Coherence Tomography Angiography (OCTA) Analysis of Ischemic vs Non-Ischemic Optic Disc Edema

This study was designed to compare optical coherence tomography angiography (OCTA) microvasculature characteristics of the optic disc and peripapillary retina in ischemic and non-ischemic optic disc edema and to compare them to normals. We hypothesized that ischemic edema would show significantly decreased vascular density when compared with non-ischemic edema and normals. Swept source OCTA imaging (Zeiss PLEX 9000) centered on the optic disc (6 X 6 mm) was performed in 17 eyes with acute ischemic optic disc edema, 22 eyes with acute optic disc edema from other causes, and 26 eyes with normal optic disc and retina. Vessel density (VD) within the superficial (SVC) and deep (DVC) vascular retinal complexes were computed. The mean superficial VD for the optic nerve in ischemic edema cases was 31.86%, compared to 36.10% in non-ischemic edema cases (p = .002) and 35.64% in normals (p = .0019); for the peripapillary retina, the means were 34.50% compared to 37.02% (p = .0006) and 34.70% (p = .8177). The mean deep VD for the optic nerve in ischemic edema cases was 30.41%, compared to 33.29% for non-ischemic cases (p = .0234) and 36.01% in normals (p = .0001); for the peripapillary retina, the means were 31.28% compared to 33.62% (p = .0217) and 35.31% (p = .0001). The optic disc and peripapillary VD were statistically significantly decreased in ischemic vs non-ischemic optic disc edema at both SVC and DVC. The findings highlight a possible role of the central retinal artery-derived circulation in ischemic optic nerve edema.