Early Signs of Glaucoma Found in Canine Sclera: Implications for Human Eye Health
Authors: C. Boote, J.R. Palko, T. Sorensen, A. Eliasy, A. Elsheikh, A.M. Komáromy, X. Pan, and J. Liu
Journal: Molecular Vision
Publication date: May 2016
Collagen anisotropy maps. Contour maps of collagen anisotropy (proportion of aligned to total fibrillar collagen) across the (A–C) carrier and (D–F) affected ADAMTS10 mutant posterior canine scleras. A region of maximum anisotropy is observed in the peripapillary sclera (arrows). Data sampling interval: 0.4 mm.
Summary:
Glaucoma is a leading cause of blindness worldwide, and researchers have long been searching for new ways to diagnose and treat this disease. In a recent study published in the journal Investigative Ophthalmology & Visual Science, we found evidence of early changes in the eye's load-bearing tissues that may help predict the development of glaucoma.
Our study focused on a canine model of open-angle glaucoma caused by an ADAMTS10 mutation. We used synchrotron wide-angle X-ray scattering to measure collagen orientation, anisotropy degree (proportion of preferentially aligned collagen), and relative density in the posterior sclera of ADAMTS10 mutant dogs and age-matched controls. We found that dogs with the ADAMTS10 mutation had significant reductions in collagen density and fibril anisotropy in the mid-posterior sclera, before any clinical signs of glaucoma were detected.
Collagen is the main load-bearing component of the eye's tunic, and changes in its microstructure could lead to mechanical changes at the macroscopic level. These changes could, in turn, interact with IOP fluctuations and affect the course of glaucoma progression. Our findings suggest that baseline scleral abnormalities may play a role in the pathophysiology of glaucoma and could potentially be used as a diagnostic tool.
It's important to note that our study had some limitations, including small sample size and variations in tissue hydration within and between specimens. However, our findings are consistent with previous research on the importance of scleral collagen structure in determining the deformation behaviour of the posterior sclera and the optic nerve head.
In conclusion, our study provides new insights into the early changes that occur in the eye's load-bearing tissues before the onset of glaucoma. These findings may have important implications for the diagnosis and treatment of this devastating disease. Future research is needed to better understand the link between scleral baseline properties and susceptibility to axonal injury in animal models of glaucoma and in human patients.