Early Macular Vessel Density Loss in Acute Ischemic Optic Neuropathy Compared to Papilledema: Implications for Pathogenesis

Purpose: To compare macular and parafoveal vasculature in patients with optic disc swelling. Methods: Twenty eyes with acute nonarteritic anterior ischemic optic neuropathy (NAION), 39 eyes with papilledema at first presentation, and 22 eyes of normal subjects were imaged using OCT-A. Macular ganglion cell complex (GCC) and peripapillary retinal nerve fiber layers thicknesses were measured in addition to macula and parafovea superficial and deep vasculature. Results: Age and gender-mixed models showed that the macular and parafoveal superficial and deep vasculature density values were significantly lower in NAION eyes than control eyes (P ≤0.0001 for allcomparisons). All vessel density values were not statistically different between papilledema eyes and control eyes. Whole superficial and deep macula vasculature in the NAION eyes (45.9±4.2 %, 50.9±6.5 %) were significantly lower than in papilledema eyes (50.5±4.6 %, 57.3±6.1 %) (P=0.03 and P=0.01, respectively). No significant differences in GCC thickness were observed among NAION, papilledema, and control eyes. Whole superficial and deep macular vasculatures, but not macular GCC thickness, were significantly correlated with visual field mean deviation (r=0.39, P=0.001 and r=0.41, P<0.001, respectively). Conclusion: Macular OCT-A is able to show early macular vasculature abnormalities associated with optic nerve damage; this change occurs before detectable macular ganglion cell complex atrophy. Vascular density correlation with visual field loss could be used as predictive measure of visual prognosis in longitudinal studies