Goniotomy is a microsurgical procedure designed to treat certain forms of glaucoma by improving the eye’s natural fluid drainage system. It is most frequently used to manage congenital glaucoma, a rare condition present at birth or shortly thereafter, but its use is expanding to specific adult cases. The core goal is to lower the elevated pressure inside the eye, preventing permanent damage to the optic nerve and preserving vision. The procedure involves making a precise incision into the eye’s drainage pathway to allow fluid to exit more effectively.
Why This Surgery is Necessary
The eye maintains internal pressure through a continuous cycle of fluid production and drainage involving aqueous humor. This fluid is produced by the ciliary body and flows into the anterior chamber, the space between the iris and the cornea. The aqueous humor must exit the eye through the trabecular meshwork, a structure located at the angle where the iris and cornea meet.
In a healthy eye, the trabecular meshwork allows fluid to pass through it and into Schlemm’s canal, which carries the fluid away. Glaucoma develops when this drainage process is impaired, leading to a buildup of aqueous humor and high intraocular pressure (IOP). This sustained pressure damages the optic nerve, causing irreversible vision loss.
Goniotomy primarily treats primary congenital glaucoma, where the drainage angle develops abnormally. The problem is a malformation of the trabecular meshwork tissue, which prevents adequate fluid outflow. The surgery corrects this developmental anomaly, creating a clear pathway for the fluid to escape and reducing the pressure inside the eye.
How the Goniotomy Procedure Works
Goniotomy is performed in an operating room under anesthesia, particularly for infants and children. The surgeon makes a tiny incision to access the anterior chamber. A specialized magnifying contact lens, called a goniolens, is placed on the eye to provide a direct view of the internal drainage angle structures.
The goniolens allows the surgeon to visualize the abnormal tissue obstructing the drainage pathway. Through the small corneal incision, a delicate micro-instrument, such as a goniotomy knife or dual blade, is introduced and maneuvered to the drainage angle.
The instrument is used to incise a portion of the abnormal trabecular meshwork tissue. This action opens the meshwork, creating a functional route for the aqueous humor to flow into the collector channels. The goal is to bypass the dysfunctional tissue and restore the natural outflow mechanism, typically lasting 15 to 20 minutes as a standalone operation.
Post-Operative Care and Expected Results
Patients are monitored briefly after goniotomy before being discharged home, often with a protective eye shield. Because sedatives are frequently used, an adult must be available to drive the patient home. Post-operative care involves using prescribed eye drops, typically antibiotics and anti-inflammatory steroids, for several weeks to prevent infection and control inflammation.
Activity restrictions are necessary, including avoiding strenuous activities, bending over, or rubbing the eye. Frequent follow-up visits with the ophthalmologist are scheduled, starting the day after surgery, to monitor intraocular pressure and ensure proper healing.
The primary result of a successful goniotomy is a significant reduction in intraocular pressure, which slows or halts the progression of optic nerve damage. For primary congenital glaucoma patients with clear corneas, the surgery has a high success rate, often above 80% in regulating pressure. If pressure is not adequately controlled, additional surgeries or long-term glaucoma medications may be necessary to maintain a safe IOP level.