Schlemm's canal, also known as canal of Schlemm or the scleral venous sinus, is a circular channel in the eye that collects aqueous humor from the anterior chamber and delivers it into the bloodstream.
The canal is essentially an endothelium-lined tube, resembling that of a lymphatic vessel. On the inside of the canal, nearest to the aqueous humor, it is covered by the trabecular meshwork, this region makes the greatest contribution to outflow resistance of the aqueous humor.
Named after Friedrich Schlemm (1795-1858), a German anatomist.
Role in glaucoma
The canal transfers approximately 2-3 microliters of aqueous humor per minute. If debris builds up, due to infection or injury in the aqueous humor, the canal is blocked and glaucoma is the result.
Canaloplasty is an advanced, nonpenetrating procedure designed to enhance and restore the eye’s natural drainage system to provide sustained reduction of intraocular pressure. Canaloplasty utilizes microcatheters in a simple and minimally invasive procedure. To perform a canaloplasty, a surgeon will create a tiny incision to gain access to Schlemm's canal. A microcatheter circumnavigates Schlemm's canal around the iris, enlarging the main drainage channel and its smaller collector channels through the injection of a sterile, gel-like material called viscoelastic. The catheter is then removed and a suture is placed within the canal and tightened. By opening Shlemm's canal, the pressure inside the eye is relieved.
- Cassin, B. and Solomon, S. Dictionary of Eye Terminology. Gainsville, Florida: Triad Publishing Company, 1990.
- Johnson MC, Kamm RD. "The role of Schlemm's canal in aqueous outflow from the human eye." Invest Ophthalmol Vis Sci. 1983 Mar;24(3):320-5. PMID 6832907.