Bulk changes in posterior scleral collagen microstructure in human high myopia

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Materials Science

Background:

• The sclera, the eye's protective outer layer, provides structural integrity.
• High myopia is associated with axial elongation and scleral thinning.
• Understanding scleral microstructure is crucial for myopia research.

Purpose of the Study:

• To investigate bulk changes in posterior scleral collagen fibril bundle architecture in human eyes with high myopia.
• To compare collagen organization between non-myopic and highly myopic sclera.

Main Methods:

• Utilized wide-angle X-ray scattering (WAXS) to map collagen orientation.
• Analyzed posterior sclera from seven non-myopic and three high myopia human eyes.
• Quantified collagen alignment and anisotropy at 0.5 mm × 0.5 mm intervals.

Main Results:

• Non-myopic sclera showed conserved microstructural features, including uniaxial alignment and a peripapillary anisotropic annulus.
• Highly myopic sclera exhibited altered peripapillary collagen, with partial loss of circumferential alignment.
• Mean fiber angle deviation in myopic peripapillary sclera was significantly higher than in controls (p<0.05).

Conclusions:

• Significant bulk alterations in posterior scleral collagen microstructure are present in high myopia.
• These changes suggest scleral remodeling during axial lengthening.
• Alterations may represent mechanical adaptations to stress in enlarged eyes.