Viscocanalostomy is a surgical procedure designed to lower intraocular pressure (IOP) in individuals with glaucoma. It creates a new pathway for the eye’s natural fluid to drain more effectively. This non-penetrating approach aims to preserve existing vision. The procedure is considered when other treatments, such as medications, have not adequately controlled eye pressure.
Understanding Viscocanalostomy
Glaucoma is a condition characterized by damage to the optic nerve, frequently associated with elevated intraocular pressure. The eye continuously produces a clear fluid called aqueous humor, which normally drains through a network of tissues, including the trabecular meshwork and Schlemm’s canal, to maintain a healthy pressure balance. In glaucoma, this drainage system can become inefficient, leading to a buildup of fluid and increased pressure within the eye.
Viscocanalostomy addresses this by improving the eye’s natural fluid outflow, targeting resistance within the trabecular meshwork. Instead of creating an entirely new, external drainage site, this procedure focuses on restoring the function of existing drainage pathways. This approach is distinct from traditional filtration surgeries, which create a direct opening for fluid to exit the eye.
The fundamental principle behind viscocanalostomy is to enhance the percolation of aqueous humor through the inner wall of Schlemm’s canal and the adjacent trabecular meshwork. By facilitating better drainage, the surgery aims to reduce intraocular pressure, mitigating further optic nerve damage.
Performing the Procedure
The viscocanalostomy procedure begins with the creation of a superficial scleral flap, a thin layer of the white outer coating of the eye. This flap is carefully lifted to expose the underlying tissues. A deeper scleral flap is then meticulously dissected, extending into the corneal limbus, the border between the cornea and the sclera.
Once these scleral flaps are prepared, the surgeon identifies Schlemm’s canal, a circular channel within the eye’s drainage system. A high-viscosity viscoelastic material is then injected into this canal. This injection gently dilates the canal, causing microscopic disruptions to its inner wall and the surrounding trabecular layers.
The inner wall of Schlemm’s canal is then carefully removed, further exposing the trabecular meshwork. This removal allows for increased aqueous outflow into a newly created scleral reservoir, a space beneath the scleral flap. The goal is to improve fluid passage from the anterior chamber into this reservoir and subsequently into the collector channels.
After the inner wall is removed and the viscoelastic material has facilitated the expansion of the canal, the scleral flaps are carefully repositioned and secured. The procedure aims to improve drainage without creating a direct, full-thickness opening into the eye’s interior. This approach seeks to avoid sudden pressure drops that can occur with other types of glaucoma surgery.
Recovery and Outcomes
Following viscocanalostomy, patients can expect a period of recovery, with regular follow-up appointments with their eye surgeon. These appointments are important for monitoring intraocular pressure and assessing the healing process. Patients will be prescribed eye drops to help reduce inflammation and prevent infection during the initial recovery phase.
Temporary restrictions may include avoiding strenuous activities, bending, or lifting heavy objects for a few weeks to prevent undue pressure on the eye. Some individuals may experience mild discomfort, redness, or blurry vision in the days immediately following the surgery. These sensations subside as the eye heals.
The expected outcome of viscocanalostomy is a reduction in intraocular pressure, typically to the mid-teens range, such as 16 to 21 mmHg. This pressure reduction aims to halt or slow the progression of glaucoma and preserve the patient’s existing vision. The procedure contributes to a more stable intraocular pressure over time.
While considered to have a favorable safety profile, temporary side effects can include minor bleeding at the front of the eye, which usually clears on its own. The long-term goal of viscocanalostomy is to provide a sustained reduction in intraocular pressure, thereby reducing the risk of further vision loss associated with glaucoma.