Purpose: To compare optic nerve head (ONH) morphology of optic nerve atrophy between eyes with primary open-angle glaucoma (POAG) and eyes with a history of non-arteritic anterior ischemic optic atrophy (NAION) using enhanced depth imaging (EDI) with spectral-domain optical coherence tomography (SD-OCT).

Design: Prospective, cross-sectional study. Participants: 121 eyes of 91 patients consisting of moderate to severe POAG (n=32 eyes), visual field mean deviation-matched NAION (n=30 eyes) and their fellow eyes (n=30 eyes), and healthy controls (n=29) Methods: The optic discs were scanned using SD-OCT and measurements were obtained using HEYEX software 6.0. Lamina cribrosa (LC) thickness, anterior LC depth (ALD), and prelaminar thickness at 3 areas (mid-superior, central, and mid-inferior) were determined. Linear mixed modeling was used to adjust for confounders including age, sex, axial length, and global peripapillary retinal nerve fiber layer (pRNFL) thickness. Main Outcome Measures: LC thickness, ALD, and prelaminar thickness were compared among the groups.

There was no significant difference in the visual field MD between the NAION (MD=-16.47± 9.05 dB) and POAG groups (MD=-16.47±9.05 vs. -16.28±9.98 dB, respectively; p>0.99), but both groups had a significantly worse MD than the healthy group (p<0.001). The NAION and POAG groups had similar pRNFL thickness (60.3±20.5 vs. 57.6±21.4 µm, respectively; p<0.99). POAG eyes had greater ALD and thinner LC than control eyes and NAION eyes in all regions of the ONH (p<0.001 for both). There was a marked prelaminar thinning in POAG eyes compared to control and NAION eyes (p<0.001). LC thickness and ALD of NAION eyes were not different from their fellow eyes and control eyes. Although prelaminar thickness was thinner in NAION eyes compared to their fellow eyes (p=0.005), it was thicker than in control eyes (p<0.001).

Despite profound thinning and posterior migration of LC in POAG, the thickness and location of LC in NAION eyes are similar to those seen in healthy control and their fellow eyes.