Abstract
Purpose :
To better understand the effects of NAION and OAG on neural and non-neural tissue in and around the disc, we used optical coherence tomography (OCT) and compared various measures including Bruch’s membrane opening-minimum rim width (BMO-MRW), horizontal rim width (BMO-HRW), and peripapillary retinal nerve fiber layer (pRNFL) thickness among patients with NAION and OAG, and healthy controls.
Methods :
10 eyes with NAION (64.9±12.2yrs), 10 eyes with OAG (66.3±14.0yrs), and 10 age-similar healthy control eyes (66.3±14.0yrs) had 12 radial line scans centered on the optic disc acquired using swept-source OCT (DRI-OCT, Topcon). OAG eyes were pairwise selected to match the NAION eyes; each pair matched in age, 24-2 mean deviation (-16.2±2.7 vs. 16.4±3.3, P=0.96), and region of field loss. A region of interest (ROI) was defined as 3 consecutive radial line scans through the portion of the disc with damage. For the ROI in NAION, OAG, and their matched controls, we determined: BMO-HRW, lamina cribrosa thickness (LCT), anterior lamina cribrosa depth (ALD), and minimum pre-laminar tissue thickness (PLT). Additionally, on each radial line scan, we measured the BMO-MRW and pRNFL (at 1.7 mm from disc center) thickness. One-way analysis of variance and the Kruskal–Wallis H test were used to compare among groups, where appropriate. Pairwise comparisons were adjusted for multiple comparisons using the Bonferroni method.
Results :
Table 1 summarizes the results. Compared to healthy eyes, NAION eyes had similar LCT [1] and BMO-MRW. Compared to OAG eyes, NAION eyes had similar pRNFL thickness, both of which were thinner than healthy eyes (Fig. 1, top, bars are ±1SE). However, NAION and healthy eyes had thicker MRW (Fig. 1, bottom), HRW, LCT and PLT than OAG eyes. Interestingly, HRW, MRW/pRNFL and HRW/pRNFL were all larger in NAION than in OAG or healthy eyes.
Conclusions :
Prelaminar and lamina cribrosa thickness, and MRW/pRNFL and HRW/pRNFL ratios, differ in NAION and OAG eyes. OCT scans of the disc may be used in distinguishing between NAION and glaucoma. 1. Fard et al., IOVS, 2016.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.