Goniotomy is a specialized, minimally invasive microsurgical procedure designed to treat glaucoma by improving the eye’s natural fluid drainage. The technique involves making a precise opening within the internal drainage system, the trabecular meshwork. This action restores the normal outflow of fluid, known as aqueous humor, which lowers the high pressure inside the eye. Historically, goniotomy has been the standard treatment for a specific type of childhood glaucoma, but its application is expanding to certain adult cases.
The Indication for Surgery
Goniotomy is the preferred initial treatment for Primary Congenital Glaucoma (PCG), a rare condition where the eye’s drainage system develops incorrectly before birth. In PCG, the trabecular meshwork is covered by an abnormal, membrane-like tissue. This congenital defect prevents the aqueous humor from exiting the eye efficiently, leading to a rapid buildup of intraocular pressure (IOP).
The primary goal of goniotomy is to restore the natural outflow pathway, reducing the IOP before sustained pressure damages the optic nerve. Because the underlying issue in PCG is an accessible physical obstruction, cutting away the obstructing tissue is highly effective. The anatomical difference in children makes goniotomy a superior option compared to treatments typically used for adult-onset glaucoma.
If the IOP is not lowered quickly, the pressure can cause the infant’s flexible eye globe to expand, leading to a stretched cornea and permanent damage to the optic nerve. Goniotomy stabilizes the eye’s anatomy and halts the progression of nerve damage. This approach is chosen over daily medication because young children require anesthesia for eye examinations, making a single surgical intervention more practical and definitive.
Understanding the Surgical Process
Goniotomy is performed in an operating room, typically under general anesthesia, ensuring the patient remains completely still. The surgeon uses a specialized magnifying contact lens, called a gonioscope or goniolens, placed on the cornea to gain a clear view of the drainage angle. This angle is located where the iris meets the cornea and houses the obstructed trabecular meshwork.
Once the angle is visualized, the surgeon introduces a fine, needle-like instrument or micro-knife through a tiny incision in the peripheral cornea. The instrument is maneuvered across the anterior chamber to reach the opposite side of the drainage angle. The surgeon then uses the tip to make a precise, circumferential incision through the abnormal tissue blocking the meshwork.
This action physically opens the obstructed tissue, creating an improved channel directly into the eye’s collector system. The incision strips away the membrane without causing trauma to surrounding structures. By incising the malformed tissue, the procedure activates the eye’s natural drainage pathway, allowing the trapped aqueous humor to flow out. The entire procedure usually takes less than 30 minutes.
Post-Operative Care and Expected Outcomes
Patients are often discharged the same day or after a short overnight stay, depending on age and anesthesia type. Post-operative care involves a regimen of antibiotic and steroid eye drops, prescribed to prevent infection and manage inflammation. Patients are advised to avoid strenuous activity, rubbing the eye, and getting water in the eye to protect the surgical site.
The surgeon schedules frequent follow-up appointments, beginning the day after surgery and continuing weekly, to monitor the IOP and the healing process. Success rates for goniotomy in treating PCG are high, often exceeding 80% when performed early before significant scarring occurs. A successful outcome is defined by the sustained reduction of intraocular pressure to a safe level.
Long-term management requires ongoing monitoring of the IOP and the optic nerve. If pressure is not adequately controlled after the first attempt, a repeat goniotomy or an additional surgical procedure may be necessary. Potential complications, though rare, include bleeding in the anterior chamber or infection. The ultimate aim is to preserve the child’s vision and prevent permanent damage.