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

Abstract

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. 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. 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). 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.