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Portland, OR, United States

Yang H.,Optic Nerve Head Research Laboratory | Thompson H.,Louisiana State University Health Sciences Center | Roberts M.D.,Optic Nerve Head Research Laboratory | Sigal I.A.,Optic Nerve Head Research Laboratory | And 2 more authors.
Investigative Ophthalmology and Visual Science | Year: 2011

PURPOSE. To retest the hypothesis that monkey ONH connective tissues become hypercompliant in early experimental glaucoma (EEG), by using 3-D histomorphometric reconstructions, and to expand the characterization of EEG connective tissue deformation to nine EEG eyes. METHODS. Trephinated ONH and peripapillary sclera from both eyes of nine monkeys that were perfusion fixed, with one normal eye at IOP 10 mm Hg and the other EEG eye at 10 (n = 3), 30 (n= 3), or 45 (n = 3) mm Hg were serial sectioned, 3-D reconstructed, 3-D delineated, and quantified with 3-D reconstruction techniques developed in prior studies by the authors. Overall, and for each monkey, intereye differences (EEG eye minus normal eye) for each parameter were calculated and compared by ANOVA. Hypercompliance in the EEG 30 and 45 eyes was assessed by ANOVA, and deformations in all nine EEG eyes were separately compared by region without regard for fixation IOP. RESULTS. Hypercompliant deformation was not significant in the overall ANOVA, but was suggested in a subset of EEG 30/45 eyes. EEG eye deformations included posterior laminar deformation, neural canal expansion, lamina cribrosa thickening, and posterior (outward) bowing of the peripapillary sclera. Maximum posterior laminar deformation and scleral canal expansion co-localized to either the inferior nasal or superior temporal quadrants in the eyes with the least deformation and involved both quadrants in the eyes achieving the greatest deformation. CONCLUSIONS. The data suggest that, in monkey EEG, ONH connective tissue hypercompliance may occur only in a subset of eyes and that early ONH connective tissue deformation is maximized in the superior temporal and/or inferior nasal quadrants. © 2011The Association for Research in Vision and Ophthalmology, Inc. Source

He L.,Optic Nerve Head Research Laboratory | Ren R.,Optic Nerve Head Research Laboratory | Yang H.,Optic Nerve Head Research Laboratory | Yang H.,Devers Eye Institute | And 9 more authors.
PLoS ONE | Year: 2014

Purpose: To quantify the effects of using the fovea to Bruch's membrane opening (FoBMO) axis as the nasal-temporal midline for 30u sectoral (clock-hour) spectral domain optical coherence tomography (SDOCT) optic nerve head (ONH) minimum rim width (MRW) and area (MRA) calculations. Methods: The internal limiting membrane and BMO were delineated within 24 radial ONH B-scans in 222 eyes of 222 participants with ocular hypertension and glaucoma. For each eye the fovea was marked within the infrared reflectance image, the FoBMO angle (h) relative to the acquired image frame (AIF) horizontal was calculated, the ONH was divided into 30usectors using a FoBMO or AIF nasal/temporal axis, and SDOCT MRW and MRA were quantified within each FoBMO vs. AIF sector. For each sector, focal rim loss was calculated as the MRW and MRA gradients (i.e. the difference between the value for that sector and the one clockwise to it divided by 30u). Sectoral FoBMO vs. AIF discordance was calculated as the difference between the FoBMO and AIF values for each sector. Generalized estimating equations were used to predict the eyes and sectors of maximum FoBMO vs. AIF discordance. Results: The mean FoBMO angle was 26.664.2u (range: 217u to +7u). FoBMO vs. AIF discordance in sectoral mean MRW and MRA was significant for 7 of 12 and 6 of 12 sectors, respectively (p,0.05, Wilcoxon test, Bonferroni correction). Eyespecific, FoBMO vs. AIF sectoral discordance was predicted by sectoral rim gradient (p,0.001) and FoBMO angle (p,0.001) and achieved maximum values of 83% for MRW and 101% for MRA. Conclusions: Using the FoBMO axis as the nasal-temporal axis to regionalize the ONH rather than a line parallel to the AIF horizontal axis significantly influences clock-hour SDOCT rim values. This effect is greatest in eyes with large FoBMO angles and sectors with focal rim loss. ©2014 He et al. Source

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