Optical Coherence Tomography Angiography of a Pale Optic Disc in Demyelinating Optic Neuritis and Ischemic Optic Neuropathy.

BACKGROUND: In the setting of a pale optic disc, distinguishing a previous episode of optic neuritis (ON) from that of nonarteritic anterior ischemic optic neuropathy (NAION) may be difficult on clinical examination. Differences in peripapillary vascular network structures, if present, might be of diagnostic utility. METHODS: Thirty-five eyes with demyelinating ON, 33 eyes with NAION, and 81 eyes of normal subjects were imaged with optical coherence tomography angiography (OCT-A) to assess peripapillary vascular density (VD). In addition, OCT was used to measure peripapillary retinal nerve fiber layer (RNFL) thickness. Areas under the receiver operating characteristic curves were used to differentiate ON vs NAION. RESULTS: NAION eyes had significantly thinner RNFL thickness than ON eyes. Age-adjusted analysis showed that the peripapillary VD values were significantly reduced in NAION (48.3 ± 7.4%) and ON eyes (54.7 ± 6.1%) compared with healthy controls (62.1 ± 4.6%); pairwise comparisons showed statistically significant differences among all 3 groups. After adjustment for severity of optic nerve injury according to mean RNFL thickness, all VD parameters were not significantly different between ON and NAION eyes. The area under the receiver operating characteristic curves for differentiating NAION from ON eyes was similar for VD (0.75) and RNFL thickness (0.74). CONCLUSIONS: Peripapillary VD measurement performs as well as RNFL thickness for distinguishing previous episodes ON and NAION. VD decline might be secondary to RNFL damage and, therefore, VD data have a limited role differentiating these 2 disorders.

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

PURPOSE: This study compares 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 optical coherence tomography angiography (OCT-A). Macular ganglion cell complex (GCC) and peripapillary retinal nerve fiber layer 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 all comparisons). 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). CONCLUSIONS: Macular OCT-A is able to show early macular vasculature abnormalities associated with optic nerve damage; this change occurs before detectable macular GCC atrophy. TRANSLATIONAL RELEVANCE: Macular vessel density measurement offers an opportunity to evaluate the optic nerve damage at initial presentation, but further longitudinal studies are needed.