Distinguish nonarteritic anterior ischemic optic neuropathy from optic neuritis by recovery of disc edema analysis

Abstract

Purpose : To compare NAION and ON

Methods : Medical records of patients who were diagnosed with unilateral NAION or ON that disc edemas were confirmed. Data from optical coherence tomography (OCT) such as structural changes of peripapillary retinal nerve fiber layer thickness (RNFLT), ganglion cell layer thickness at two time points of first diagnosis and stable states. Severity and recovery speed of disc edema, durations of disc edema exist was compared between two groups. And clinical factors significantly correlated with the velocity were identified. The study included 33 eyes of NAION and 33 eyes in ON.

Results : Mean age of NAION, 69.1±11.8 was older than 51.7±15.7 years of ON (P<0.001). Periods of disc edema exists were 1.5 months in NAION and 1.3 months in ON (P=0.16). At diagnosis, mean peripapillary RNFLT of NAION, 215.7 um was not different with 199.1 um of ON (P= 0.25) and recovery speed of disc edema was not significantly different between two disease (P= 0.99). In both diseases, the more severe the disc swelling was, the longer the swelling lasted (r=0.34, P<0.05 in NAION, r=0.51, P=0.002 in ON) and the the faster recovery rate (r=0.61, P<0.001 in NAION, r=0.35, P=0.04 in ON).

Conclusions : The recovery speed of disc swelling, which did not differ significantly, cannot be used as a clue to distinguish between NAION and ON. In both diseases, the more severe the initial disc swelling was, the longer the edema existed, but the recovery speed was faster.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.

 

Figure 1. Changes of disc edema and visual field defect in NAION and ON. Figures (A-F) are about NAION and Figures (G-L) are about ON. In the early stages of both diseases, optic disc edema is observed (A, C in NAION, G, I in ON), and diffuse visual field defects are observed (B in NAION, H in ON). With the passage of time, optic disc edema in funduscopy (D) and OCT (F) was resolved but inferior altitudinal field defect was remained (E) in NAION. In contrast to this, visual field (K) was completely recovered in chronic stage as optic disc edema (J,L) recovers in ON. In this way, it is difficult to distinguish between the two diseases in the acute phase, we designed this study to distinguish them based on the recovery period and pattern of the disc edema.