Abstract
Purpose:
Previous studies in living normal and glaucomatous eyes have separately examined lamina cribrosa microarchitecture or optic nerve head (ONH) geometry. The purpose of this study is to compare ONH geometry and anterior lamina cribrosa surface (ALCS) microarchitecture between normal subjects and patients with primary open-angle glaucoma (POAG).
Methods:
Spectral domain optical coherence tomography (SDOCT) [Spectralis HRA+OCT] and adaptive optics scanning laser ophthalmoscope (AOSLO) images of the ONH and ALCS microarchitecture were acquired in 13 eyes undergoing treatment as glaucoma suspects or as having early to moderate POAG, and in 25 age-matched normal eyes. ONH features were semi-manually marked in SDOCT radial B-scans to calculate Bruch’s membrane opening (BMO) area, mean ALCS depth (ALCSD), mean ALCS radius of curvature (RoC), prelaminar tissue volume (PTV), mean minimum rim width (MRW) and rim volume. Anterior laminar pores were manually marked in AOSLO images and 3D transformed to calculate mean global ALCS pore area and elongation. A Mann-Whitney rank sum test was used to assess statistical differences in all parameters between groups.
Results:
Mean MRW (203.9 ± 29.4 µm vs 287.9 ± 36.2 µm) and rim volume (0.227 ± 0.06 mm3 vs 0.413 ± 0.12 mm3) were significantly reduced in glaucoma/glaucoma-suspects compared to normal subjects (P<.05). Mean ALCSD (465.5 ± 110 µm vs 342.6 ± 82.3 µm) was larger (i.e., deeper) while mean RoC (2.92 ± 0.59 mm vs 3.96 ± 1.24 mm) was smaller (i.e., more curved) in glaucoma/glaucoma-suspects versus normal subjects (P<.05). However, BMO area (2.18 ± 0.49 mm2 vs 2.09 ± 0.52 mm2) and PTV (0.923 ± 0.18 mm3 vs 0.978 ± 0.18 mm3) were statistically similar between groups (P>.05). Mean ALCS pore area (1,880 ± 440 µm2 vs 1,982 ± 565 µm2, P>.05) and elongation (2.07 ± 0.17 vs 2.00 ± 0.22, P>.05) were also similar between glaucoma/glaucoma-suspects and normal subjects, respectively.
Conclusions:
Early glaucoma/glaucoma-suspects and age-matched normal subjects have statistically similar global ALCS pore microarchitecture despite having statistically different ONH geometries. Further analyses are required to determine whether differences in ALCS pore geometry exist locally between groups.