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Amitabha S. Bhakta, Danica J. Marrelli, Nripun Sredar, Kevin M. Ivers, Hope M. Queener, Jason Porter; Characterizing lamina cribrosa and optic nerve head geometry in normal human eyes. Journal of Vision 2013;13(15):P35. doi: 10.1167/13.15.70.
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© ARVO (1962-2015); The Authors (2016-present)
Several studies suggest that retinal ganglion cell axons are first damaged at the level of the lamina cribrosa in glaucoma. It is important to understand the normal variability in lamina cribrosa and optic nerve head (ONH) geometry before examining changes in these structures during glaucoma. Spectral domain optical coherence tomography (SDOCT) and adaptive optics scanning laser ophthalmoscope (AOSLO) images of the lamina cribrosa and ONH were acquired in fellow eyes of 29 normal human subjects (36.5 ± 16.6 years). Anterior lamina cribrosa surface (ALCS) and ONH features were manually marked in SDOCT radial B-scans (centered on the ONH) to calculate Bruch's Membrane Opening (BMO) area, mean ALCS depth from the BMO reference plane, mean ALCS radius of curvature (RoC), prelaminar tissue volume and rim volume. Laminar pores were manually marked in AOSLO images and 3D transformed to calculate pore area, elongation and nearest neighbor distance. ONH and anterior laminar pore parameters were not statistically different between fellow eyes of normal subjects. Eyes with longer axial lengths had larger BMO areas (P=.02). In addition, eyes with larger BMO areas typically had increased prelaminar tissue volumes (P<.01) and larger mean pore areas (P<.01) independent of the mean ALCS depth. Rim volume increased with prelaminar tissue volume (P<.01). ALCS RoC was independent of any measured ONH or laminar parameter. These normative measurements will be used for comparison with ONH and laminar microstructure values measured in glaucomatous eyes and could potentially provide insights on whether these structures change during normal aging.
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