Ultrastructural characteristics of the trabecular meshwork in primary open-angle glaucoma versus chronic...

Area of Science:

• Ophthalmology
• Cell Biology
• Biomedical Engineering

Background:

• The trabecular meshwork (TM) regulates intraocular pressure (IOP), a key glaucoma risk factor.
• Understanding TM ultrastructure in different glaucoma types is crucial for disease mechanisms.

Purpose of the Study:

• Compare TM ultrastructure in primary open-angle glaucoma (POAG) and chronic angle-closure glaucoma (CACG).
• Utilize transmission electron microscopy (TEM) for detailed analysis.

Main Methods:

• Obtained TM specimens from POAG and CACG patients via Kahook Dual Blade goniotomy.
• Evaluated cellular morphology, extracellular matrix (ECM) organization, and collagen fibril architecture (Feret's diameter).
• Introduced an Organelle Severity Index (OSI) to assess subcellular stress.

Main Results:

• Both POAG and CACG exhibited sparse TM cellularity and significant subcellular stress.
• Collagen fibrils were significantly larger in CACG (60.27 nm) compared to POAG (43.61 nm).
• No significant correlation found between OSI scores and preoperative clinical metrics.

Conclusions:

• POAG and CACG share a common pathway of TM cellular reduction and structural disruption.
• Distinct collagen fibril architectures suggest divergent ECM remodeling in POAG vs. CACG.
• These differences may influence subtype-specific outflow resistance and glaucoma pathogenesis.