Schlemm's canal: the outflow 'vessel'

Area of Science:

• Ophthalmology
• Anatomy
• Physiology

Background:

• Glaucoma affects 60 million worldwide, characterized by elevated intraocular pressure (IOP).
• Increased resistance to aqueous humor (AH) outflow in the juxtacanalicular meshwork is a primary cause of elevated IOP in glaucoma.
• Understanding the conventional aqueous humor drainage pathway is critical for glaucoma research.

Purpose of the Study:

• To comprehensively review the morphology of Schlemm's canal (SC) and aqueous humor pathways.
• To discuss the role of SC in glaucoma development and outflow resistance.
• To present channelography as a method for assessing the conventional drainage pathway.

Main Methods:

• Review of existing literature on ocular anatomy and physiology related to aqueous humor outflow.
• Detailed description of the aqueous humor pathway from the anterior chamber to episcleral veins.
• Introduction and explanation of channelography for evaluating collector and aqueous veins.

Main Results:

• The review delineates the complete path of aqueous humor flow through the trabecular meshwork, collector channels, and into episcleral veins.
• It highlights the significance of Schlemm's canal in regulating outflow resistance and its implication in glaucoma.
• Channelography is identified as a precise technique for assessing the conventional drainage pathway and identifying specific venous structures.

Conclusions:

• The morphology of Schlemm's canal and associated pathways are integral to maintaining normal intraocular pressure.
• Disruptions in these pathways, particularly at the juxtacanalicular meshwork, contribute significantly to glaucoma pathogenesis.
• Channelography offers a valuable tool for in-vivo assessment of the conventional outflow pathway, aiding in glaucoma diagnosis and management.