Trabecular meshwork in pseudoexfoliation syndrome with and without open-angle glaucoma. A morphometric,...

Area of Science:

• Ophthalmology
• Glaucoma Research
• Cell Biology

Background:

• Pseudoexfoliation (PEX) syndrome is a common cause of secondary glaucoma.
• The exact mechanisms of glaucoma development in PEX syndrome are not fully understood.
• Investigating the role of PEX material and other substances in the trabecular meshwork is crucial.

Purpose of the Study:

• To test the hypothesis that glaucoma in PEX syndrome results from blockage of outflow channels by PEX material, melanin, or both.
• To determine the origin of intratrabecular PEX material.

Main Methods:

• Trabecular meshwork tissue was analyzed from eyes with PEX glaucoma, PEX syndrome without glaucoma, and control eyes.
• Morphometric methods quantified PEX material, melanin, plaque, cells, and open spaces.
• Electron microscopy examined the filtration area and juxtacanalicular tissue (JCT).

Main Results:

• PEX deposits were primarily in the JCT and uveal meshwork, independent of glaucoma.
• Local production of PEX fibers in the JCT was observed, with some PEX material originating from aqueous humor.
• Glaucoma correlated significantly with PEX material amount, JCT thickness, and Schlemm's canal area.

Conclusions:

• Mechanical obstruction by PEX material and local production by trabecular cells are key factors in PEX glaucoma.
• Accumulation of PEX material in the JCT leads to endothelial cell dysfunction and JCT/Schlemm's canal disorganization.
• These factors contribute to a unique form of secondary open-angle glaucoma in PEX syndrome.