The trabecular meshwork in acute and chronic angle closure glaucoma.

Area of Science:

• Ophthalmology
• Glaucoma Research
• Cell Biology

Background:

• Primary angle closure glaucoma (PACG) is a leading cause of irreversible blindness worldwide.
• Understanding the structural changes in the trabecular meshwork (TM) is crucial for managing PACG.
• The TM regulates aqueous humor outflow, and its dysfunction leads to elevated intraocular pressure (IOP).

Purpose of the Study:

• To investigate the effects of acute and chronic primary angle closure glaucoma (PACG) on the microscopic structure of the trabecular meshwork.
• To differentiate the pathological changes in the TM between acute and chronic PACG.
• To assess the correlation between gonioscopic findings and TM damage.

Main Methods:

• Trabecular specimens were obtained from 16 PACG patients (6 acute, 10 chronic).
• Light and electron microscopy were utilized for detailed structural analysis.
• Histopathological examination focused on TM architecture, cellular components, and pigment deposition.

Main Results:

• Acute PACG: Generalized edema, pigment accumulation in TM spaces and Schlemm's canal, and attenuated endothelial cells were observed.
• Chronic PACG: Disrupted TM architecture, reduced TM spaces, fused beams, electron-dense bodies, endothelial cell loss, and melanin pigment were noted.
• TM damage was evident even in areas without peripheral anterior synechiae.

Conclusions:

• Acute PACG is characterized by pigmentary changes and non-inflammatory degeneration of the TM.
• Chronic PACG involves endothelial cell loss and reactive repair processes, leading to architectural distortion.
• Gonioscopy may underestimate TM damage; long-term IOP monitoring is essential after acute PACG due to potential late complications.