'What controls aqueous humour outflow resistance?'

Area of Science:

• Ophthalmology
• Fluid Dynamics
• Cell Biology

Background:

• Aqueous humour outflow resistance is a key factor in intraocular pressure regulation.
• The inner wall endothelium of Schlemm's canal is implicated in this resistance in both normal and glaucomatous eyes.

Purpose of the Study:

• To investigate the precise location and mechanisms of aqueous humour outflow resistance.
• To understand the role of giant vacuoles and pores in Schlemm's canal endothelium in regulating fluid flow.
• To explore potential differences in these mechanisms between normal and glaucomatous eyes.

Main Methods:

• Analysis of fluid flow resistance in the inner wall endothelium of Schlemm's canal.
• Examination of the role of giant vacuoles and pores in endothelial cells.
• Consideration of extracellular matrix and basement membrane contributions to resistance.

Main Results:

• The majority of aqueous humour outflow resistance is located in or near the inner wall endothelium of Schlemm's canal.
• Fluid flow is influenced by vacuoles and pores within the endothelium.
• Resistance is likely generated in the juxtacanalicular connective tissue's extracellular matrix or Schlemm's canal's basement membrane.

Conclusions:

• Aqueous humour outflow resistance is primarily determined by factors within or adjacent to the Schlemm's canal inner wall endothelium.
• Further in vitro studies are needed to elucidate vacuole and pore formation and their reduction in glaucoma.