TEM Images

Compressed file containing TEM images of en face and transverse section of dense disorganized collagen substrate after cyclic loadin

MechanicalTestingData

Compressed file containing raw force data of the cyclic loading experiments

X-ray scattering data analysis.

<p>A) WAXS pattern from peripapillary human sclera. The spread of x-ray scatter intensity as a function of azimuth angle, φ, around the collagen intermolecular reflection (arrow) contains information about the orientation distribution of fibrils. B) Power-law background function (broken line) fitted to a radial profile (solid line) through pattern shown in A. For each pattern, independent background functions were fitted and subtracted along 256 equally spaced radial directions (every 1.4°), enabling the collagen signal to be isolated and extracted in two dimensions. <i>Arrow:</i> Collagen peak. C) Angular x-ray scatter intensity profile of pattern shown in A. The scatter intensity may be separated into that arising from isotropic collagen, Ii, and that arising from preferentially aligned fibrils, Ia. D) Aligned collagen scatter displayed in a polar coordinate system. The plot shape reveals the collagen anisotropy. The length of vector, r(φ), is proportional to the relative number of fibrils preferentially aligned at angle, φ+π/2.</p

Location of scleral canal using x-ray data.

<p>A) Map of total collagen x-ray scatter across a mid-stromal section of the human peripapillary sclera and ONH. Smaller scatter values, indicative of lower collagen density, typify the central, porous lamina cribrosa. B) Vertical data transect through the map shown in A). The abrupt reduction in collagen scatter when passing from the peripapillary sclera into the lamina may be used to locate the scleral canal edge (<i>arrows</i>).</p

Results of the general linear mixed model with spatial autocorrelation for the degree of fiber alignment in the peripapillary sclera with glaucoma diagnosis, quadrant, and diabetes history as explanatory variables.

<p>The variogram for the degree of fiber alignment increased and then leveled off as distance between 2 measurements of a same specimen increased, indicating spatial autocorrelation. S stands for superior, N for nasal, I for inferior, and T for temporal.</p

Collagen fiber alignment.

<p>Box plot of the average degree of fiber alignment in each of the 4 quadrants of the peripapillary sclera for normal, undamaged glaucoma, and damaged glaucoma specimens. The degree of fiber alignment was defined from the WAXS scatter intensity as the ratio of the aligned scatter to the total scatter (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0131396#pone.0131396.g003" target="_blank">Fig 3</a>). A scatter plot is superimposed to represent individual data points. Significant differences in degree of fiber alignment between two quadrants are indicated by connecting brackets (adjusted <i>p</i> ≤ 0.05).</p

Statistical comparison of mean collagen anisotropy at different depths for the superior-temporal peripapillary scleral quadrant (two-tailed t-tests).

<p>Significance is indicated at three probability levels</p><p>* p < 0.05</p><p>** p < 0.01</p><p>*** p < 0.001.</p><p>Statistical comparison of mean collagen anisotropy at different depths for the superior-temporal peripapillary scleral quadrant (two-tailed t-tests).</p

Anisotropy depth-profiles.

<p>Mean collagen anisotropy vs depth (mid-section), by peripapillary region, averaged over eight human scleras. A) Bar charts to show trend in separate regions, where bar height represents mean and error bars denote standard deviation. B) Composite graph showing trend in mean for all regions.</p

Statistical comparison of mean collagen anisotropy at different depths for the inferior-temporal peripapillary scleral quadrant (two-tailed t-tests).

<p>Significance is indicated at three probability levels</p><p>* p < 0.05</p><p>** p < 0.01</p><p>*** p < 0.001.</p><p>Statistical comparison of mean collagen anisotropy at different depths for the inferior-temporal peripapillary scleral quadrant (two-tailed t-tests).</p

Comparison of circumferential collagen and lamina insertion depths.

<p>Schematic of human optic nerve and peripapillary sclera cross-section, showing the location of the circumferential scleral collagen, as determined by WAXS, in relation to the typical position of the lamina cribrosa in a generic middle-aged/elderly normal human eye. % circumferential alignment is expressed as mean anisotropy, averaged over the four quadrants of eight eyes. *Distances of lamina insertion sites (average and range) are taken from the literature[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0118648#pone.0118648.ref020" target="_blank">20</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0118648#pone.0118648.ref022" target="_blank">22</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0118648#pone.0118648.ref026" target="_blank">26</a>].</p