Bulk changes in posterior scleral collagen microstructure in human high myopia

Authors: Petar Markov (Cardiff University) , Ashkan Eliasy (University of Liverpool) , Jacek K. Pijanka (Cardiff University) , Hla M. Htoon (Singapore Eye Research Institute (SERI)) , Neil G. Paterson (Diamond Light Source) , Thomas Sorensen (Diamond Light Source) , Ahmed Elsheikh (University of Liverpool; Moorfields Eye Hospital NHS Foundation Trust; UCL Institute of Ophthalmology; Beihang University) , Michael J.a. Girard (Singapore Eye Research Institute (SERI); National University of Singapore) , Craig Boote (University of Cardiff; National University of Singapore)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Molecular Vision , VOL 24 , PAGES 818-833

State: Published (Approved)
Published: December 2018
Diamond Proposal Number(s): 11316 , 14757

Abstract: Purpose: We aimed to characterize any bulk changes in posterior scleral collagen fibril bundle architecture in human eyes with high myopia. Methods: Wide-angle X-ray scattering (WAXS) was employed to map collagen orientation at 0.5 mm × 0.5 mm spatial intervals across the posterior sclera of seven non-myopic human eyes and three eyes with high myopia (>6D of refractive error). At each sampled point, WAXS provided thickness-averaged measures of the angular distribution of preferentially aligned collagen fibrils within the tissue plane and the anisotropic proportion (the ratio of preferentially aligned to total collagen scatter). Results: Non-myopic specimens featured well-conserved microstructural features, including strong uniaxial collagen alignment along the extraocular muscle insertion sites of the mid-posterior sclera and a highly anisotropic annulus of collagen circumscribing the nerve head in the peripapillary sclera. All three myopic specimens exhibited notable alterations in the peripapillary sclera, including a partial loss of circumferential collagen alignment and a redistribution of the normally observed regional pattern of collagen anisotropic proportion. Linear mixed-model analysis indicated that the mean fiber angle deviation from the circumferential orientation in the peripapillary sclera of highly myopic eyes (23.9° ± 18.2) was statistically significantly higher than that of controls (17.9° ± 12.0; p<0.05). Conclusions: Bulk alterations in the normal posterior scleral collagen microstructure occur in human eyes with high myopia. These changes could reflect remodeling of the posterior sclera during axial lengthening and/or a mechanical adaption to tissue stresses induced by fluid pressure or eye movements that may be exacerbated in enlarged eyes.

Subject Areas: Biology and Bio-materials

Instruments: I02-Macromolecular Crystallography , I03-Macromolecular Crystallography

Added On: 11/01/2019 10:52

Discipline Tags:

Health & Wellbeing Structural biology Ophthalmology Life Sciences & Biotech

Technical Tags:

Diffraction Macromolecular Crystallography (MX)