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Howard Lockwood, Juan Reynaud, Jonathan Grimm, Hongli Yang, Stuart Gardiner, J Crawford Downs, Claude Burgoyne; 3D Quantification of Laminar Microarchitecture (LMA) in Normal Non-Human Primate (NHP) Eyes. Invest. Ophthalmol. Vis. Sci. 2012;53(14):2825.
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© ARVO (1962-2015); The Authors (2016-present)
To calculate and characterize the regional distributions of lamina cribrosa beam diameter (BD), pore diameter (PD), connective tissue volume (CTV) and connective tissue volume fraction (CTVF) from high-resolution, digital 3D optic nerve head (ONH) reconstructions of 17 normal NHP eyes.
The ONH reconstructions were 3D-aligned to a clinical photograph or confocal scanning laser tomographic (CSLT) image and the lamina cribrosa was 3D segmented [IEEE Trans Med Imag, 2006; 25:245-255]. Each voxel was assigned a "diameter" value based upon the largest sphere that fit inside the "beam" or "pore" in which it was contained. CTV was defined to be the total volume of beam voxels. CTVF was defined to be the ratio of CTV to total volume (pore + beam voxels). For each ONH, BD, PD, CTV and CTVF data were digitally converted to right eye orientation and mapped to a cylinder of radius 1.5 mm and 120 μm thickness. Data were regionalized by clock hour using the BMO-centroid to foveal axis as the horizontal midline allowing direct comparisons between eyes with varying laminar and scleral geometries.
Regional BD and PD did not deviate significantly from a normal distribution according to the Shapiro-Wilk test. Generalized estimating equation models were constructed using the distance from the horizontal to determine parameter variability nearer the superior and inferior poles. Beams were slightly thinner within the vertical compared to the horizontal clock hours (p=0.05, see above).
These data expand our previous characterizations of normal NHP LMA [J. Grimm et al, ARVO, 2007; Roberts, et al IOVS. 2009;50:681-690] to include laminar BD, PD, CTV and CTVF in 17 normal eyes. The regional distributions of normal NHP laminar BD, PD, CTV and CTVF are eye-specific (data not shown). However pooled data for all 17 eyes (see Figure) suggest that on average, BD is greatest temporally, PD is greatest inferior and superior temporally, CTV is greatest superiorly and inferiorly, and laminar connective tissue density (CTVF) is greatest temporally.
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