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. 2015 Dec 7;56(13):7661–7678. doi: 10.1167/iovs.15-17624

Figure 1.

Figure 1

Five connective tissue phenomena underlie ONH cupping in monkey EG: (1) laminar deformation, (2) scleral canal expansion, (3) laminar insertion migration, (4) laminar thickness change, and (5) posterior bowing of the peripapillary sclera. Our parameter post-BMO total prelaminar volume (light green in left column and light blue in middle column) captures three of these phenomena and serves as a surrogate measure of overall ONH laminar/scleral canal deformation within a given EG eye. The following landmarks are delineated within representative superior temporal (ST) to inferior nasal (IN) digital sections from the control (left) and EG (middle) eye of four representative animals (monkeys 1, 12, 18, and 21, respectively) that span the full range of EG versus control eye post-BMO total prelaminar volume difference (36%–578%): anterior scleral/laminar surface (white dots), posterior scleral/laminar surface (black dots), neural boundary (green dots), BMO reference plane (red line), and BMO centroid (vertical blue line). Delineated points for the control (solid lines) and EG (dotted) eye of each animal are overlaid relative to the BMO centroid in the schematic diagrams on the right. For each animal, post-BMO total prelaminar volume is outlined in both the control (light green, left) and EG (light blue, middle) eye for qualitative comparison. The overlaid delineations for both eyes of each animal in the right column make it clear that EG eye post-BMO total prelaminar volume expansion is due to the combination of posterior laminar deformation, scleral canal expansion and outward migration of the anterior laminar insertion. Post-BMO total prelaminar volume expansion is present within monkey 1 and progresses through more advanced stages of connective tissue deformation and remodeling (monkeys 12, 18, and 21; Fig. 3). The phenomena that underlie post-BMO total prelaminar volume expansion are accompanied by laminar thickening in the EG eyes with the least post-BMO total prelaminar volume change (monkeys 1 and 12), thickening that is progressively diminished in magnitude in eyes with moderate post-BMO total prelaminar volume change (monkey 18) and laminar thinning in the eyes with the largest post-BMO total prelaminar volume change (monkey 21; see Fig. 4 for more details). Outward migration of the laminar insertions is apparent in monkeys 12, 18, and 21 (also see Fig. 4). Outward bowing of the peripapillary sclera is present in the majority of EG eyes (Fig. 5). Here it is evident in the right column schematic overlays for monkeys 12 and 21 by the fact that the EG eye anterior sclera (white dotted line delineations) are anterior to the control eye anterior sclera (white solid line delineations). Reprinted with permission from Burgoyne C. The morphological difference between glaucoma and other optic neuropathies. J Neuroophthalmol. 2015 Sep;(35 suppl 1):S8–S21. © 2015 by the North American Neuro-Ophthalmology Society.