A glaucoma implant is a small medical device surgically placed in the eye to help manage glaucoma, a condition that can lead to vision loss. Also known as an aqueous shunt or tube shunt, this device creates an alternative pathway for fluid to drain from the eye. Its purpose is to lower intraocular pressure (IOP), a significant factor in glaucoma progression, thereby protecting the optic nerve from further damage.
Understanding Glaucoma Implants
Glaucoma is a group of eye diseases characterized by damage to the optic nerve, often linked to elevated intraocular pressure. This pressure increases when the eye’s internal fluid, called aqueous humor, does not drain properly. Sustained high pressure can harm the optic nerve, potentially leading to irreversible vision loss.
Glaucoma implants are considered for individuals whose intraocular pressure remains too high despite other treatments, such as eye drops or laser therapy. They are also used in complex cases, including those resulting from injury, congenital conditions, or neovascular glaucoma, where scar tissue might interfere with other surgical methods. The implant bypasses non-functioning natural drainage pathways, providing a new route for fluid outflow to reduce eye pressure. While implants cannot restore lost vision, they aim to preserve existing vision by maintaining healthier eye pressure.
How Glaucoma Implants Function
Glaucoma implants operate by creating a new drainage system for the aqueous humor. Each implant consists of a soft, flexible tube connected to a small plate or reservoir. The tube is inserted into the anterior chamber of the eye, which is the space between the cornea and the iris.
The fluid collects in a small pool, often called a bleb, over the plate. From this reservoir, the fluid is gradually absorbed by the body’s natural systems, including capillaries and the lymphatic system, thereby lowering the eye’s internal pressure. Some implants feature a valve to regulate fluid flow (valved implants), while others are non-valved, managing flow through other mechanisms.
The Surgical Procedure
Glaucoma implant surgery is performed in an outpatient surgery center or hospital setting and takes about one to two hours. Prior to the procedure, patients may be instructed to stop certain medications, such as blood thinners, to reduce the risk of bleeding. Upon arrival, the area around the eye is cleaned, and a sterile drape is applied.
Anesthesia is administered, typically local anesthesia to numb the eye area, combined with medication to help the patient relax. The surgeon begins by making a small incision in the conjunctiva, the clear membrane covering the white part of the eye. A pocket is created underneath the conjunctiva and on the sclera, where the implant’s plate is positioned and secured with sutures. The small tube attached to the plate is then inserted into the anterior chamber of the eye, often between the cornea and the iris. The incision is then closed.
Recovery and Long-Term Care
Following glaucoma implant surgery, patients can expect a recovery period with specific post-operative care. Immediately after the procedure, the eye may be patched, sometimes overnight, and temporary blurred vision or mild discomfort is common for several days to a few weeks. Patients are advised to avoid strenuous activities, bending over, straining, or lifting heavy objects during the initial recovery phase.
Patients will be prescribed eye drops for several weeks to prevent infection, manage inflammation, and reduce scarring. Regular follow-up appointments with the ophthalmologist are scheduled in the weeks and months after surgery to monitor eye pressure and assess healing. It can take three months or longer for the intraocular pressure to stabilize as the capsule around the implant’s plate matures. While many patients may reduce or discontinue some glaucoma medications, continued monitoring and adherence to a long-term care plan are necessary to ensure stable eye pressure and preserve vision.