A trabeculectomy is a surgery performed on the eye to lower its internal pressure. The procedure creates a new drainage path for eye fluid to manage conditions causing elevated intraocular pressure (IOP), most commonly glaucoma. This intervention is designed to prevent further damage to the optic nerve and subsequent vision loss, but it does not restore vision that has already been lost.
Purpose of a Trabeculectomy
Glaucoma is a condition of high pressure inside the eye that can damage the optic nerve, which transmits visual information to the brain. This damage often leads to a gradual loss of peripheral vision and can result in total blindness if untreated. Standard treatments for glaucoma begin with medicated eye drops or office-based laser therapies designed to lower the IOP.
A trabeculectomy is considered when initial treatments fail to control the eye’s internal pressure. It is recommended for patients with progressing glaucoma, including open-angle and closed-angle forms. The surgery’s purpose is not to cure glaucoma but to create a lower-pressure environment within the eye, halting further damage to the optic nerve and preserving remaining sight.
The Surgical Procedure
A trabeculectomy is an outpatient procedure that takes about an hour. Patients may be awake with a numbed eye or under general anesthesia. The surgeon begins by making a small flap in the sclera, the white outer layer of the eye, in an area concealed by the upper eyelid. This incision provides access to the underlying drainage structures.
Beneath this scleral flap, the surgeon removes a tiny piece of the trabecular meshwork, the eye’s natural drainage system that is functioning poorly. This creates a new channel for the aqueous humor—the clear fluid in the front of the eye—to exit. This pathway bypasses the dysfunctional natural drain, allowing fluid to flow out more freely and lowering the intraocular pressure.
To complete the procedure, the surgeon covers the new opening with the conjunctiva, the thin tissue covering the sclera. This forms a small reservoir called a “bleb” on the eye’s surface, hidden by the eyelid. Fluid that collects in this bleb is absorbed into surrounding blood vessels, maintaining a lower pressure within the eye. An anti-scarring medication may be applied during surgery to help prevent the new drainage site from closing.
The Recovery Process
Immediately after surgery, the eye is covered with a patch or protective shield, which patients are required to wear while sleeping for several weeks to prevent accidental pressure or rubbing. Vision in the operated eye is often blurry, and the eye may feel irritated, red, and swollen. Careful adherence to all post-operative instructions is required for success.
A strict regimen of medicated eye drops is part of the healing process. Patients are prescribed antibiotic drops to prevent infection and steroid drops to reduce inflammation and inhibit scarring that could close the new drainage channel. Activity restrictions include avoiding heavy lifting, bending, strenuous exercise, and swimming for several weeks to prevent spikes in eye pressure.
Frequent follow-up appointments begin the day after surgery and continue for several weeks. These visits allow the surgeon to monitor intraocular pressure, assess the bleb’s health, and make adjustments to the treatment plan. For instance, the surgeon may remove or loosen sutures to fine-tune the rate of fluid drainage.
Long-Term Management and Potential Complications
A successful trabeculectomy controls eye pressure for years, often reducing or eliminating the need for glaucoma medications. Some patients may still require eye drops to maintain the target pressure, though at a lower dosage than before surgery. Regular, lifelong monitoring by an eye care specialist is necessary.
The most common reason for the surgery to fail over time is scarring. The body’s natural healing process can cause scar tissue to form over the bleb, closing the drainage channel and causing the IOP to rise again. This is managed with the anti-scarring medications used during surgery and careful monitoring during follow-up visits.
Other potential complications, though less common, can occur. Hypotony, a condition where eye pressure becomes too low, can result from excessive drainage. A small, lifelong risk of infection also exists, as the bleb provides a potential entry point for bacteria. The surgery can also accelerate the development of cataracts. If the trabeculectomy fails, other options like drainage tube devices may be considered.