Glaucoma is a progressive eye disease that damages the optic nerve, often due to elevated intraocular pressure. This pressure builds up when the eye’s internal fluid, aqueous humor, cannot drain properly. For advanced cases that do not respond to medication or laser treatments, a surgical solution often becomes necessary.
A glaucoma drainage device, commonly called an eye shunt, acts as a bypass system to lower this pressure. The device consists of a small silicone tube connected to a flat plate. The tube drains the aqueous humor to the plate, which is positioned on the sclera (white part of the eye), where the fluid is absorbed by surrounding tissue. This mechanism creates a new, stable outflow pathway to prevent further vision loss.
Is Eye Shunt Removal Possible?
An eye shunt can be removed, but this is considered an uncommon event. Glaucoma drainage devices are designed to be permanent fixtures, providing a long-term solution for pressure control after less invasive treatments have failed. Removing a functioning device is a serious decision, as it eliminates the primary mechanism controlling the patient’s intraocular pressure.
Removal is reserved for situations where the device causes an unresolvable problem or complication, and revision or repair has failed. In rare instances, if a patient’s natural drainage system stabilizes years after implantation, surgeons usually prefer to tie off or occlude the tube rather than extract the entire device. Removal is a major procedure performed only when the risks of keeping the device outweigh the risks of extraction.
Indicators for Surgical Extraction
Device Erosion and Infection
A primary indication for removal is device erosion, where the shunt’s tube or plate becomes exposed through the overlying conjunctiva. This exposure risks a severe eye infection called endophthalmitis, which can cause rapid vision loss. Exposed devices require immediate intervention and often complete extraction if the erosion cannot be patched or covered.
Chronic inflammation or infection localized around the plate or tube also necessitates removal. Since infections in this area are difficult to eliminate with antibiotics, the shunt can act as a source for recurrent infection. Removing the device is often the only way to ensure the long-term health of the eye.
Hypotony and Malfunction
Another indicator is hypotony, a condition where intraocular pressure drops dangerously low due to over-filtration. While this can sometimes be managed with surgical revisions, permanent, unmanageable hypotony damages the eye’s internal structures. In these specific cases, the drainage device may need to be removed to allow the pressure to return to a healthier level.
Device malfunction, such as tube blockage that cannot be cleared or significant plate migration, may also necessitate extraction. If the shunt is no longer controlling pressure and cannot be salvaged with a minor revision, replacing it with a new device or using a different surgical approach requires removing the old implant first.
The Procedure for Removing the Device
The extraction of an eye shunt is a complex procedure, usually performed in an outpatient surgical center under local anesthesia with sedation. The surgeon makes an incision in the conjunctiva to access the implant and uses blunt dissection to separate the surrounding scar tissue (capsule) that has formed around the plate.
Once exposed, the tube is carefully grasped near where it enters the eye and pulled gently from the anterior chamber. The surgeon then works to free the entire plate, which is often secured to the sclera with sutures, by cutting the anchoring sutures and separating the plate from the eye wall. The entire device is then removed as a single unit.
A key step involves managing the sclerostomy, the site where the tube entered the eye. This opening must be securely sealed with fine sutures to prevent fluid leakage and re-establish structural integrity. Finally, the surgeon closes the conjunctiva over the area where the plate was located, sometimes using a tissue graft to ensure a strong, leak-proof closure.
Long-Term Glaucoma Management Post-Removal
Following device removal, the primary concern is controlling intraocular pressure, which is expected to rise since the artificial drainage pathway is lost. Patients require intensive post-operative monitoring to manage this pressure spike.
The first line of defense involves resuming or significantly increasing the patient’s glaucoma medication regimen. Topical drops and sometimes oral medications are used to suppress aqueous humor production and achieve a safe target pressure. This medical management is often temporary while the eye heals and the long-term strategy is determined.
Many patients eventually require a replacement surgical procedure to re-establish drainage. This may involve implanting a new shunt in a different quadrant of the eye, away from the scarring of the first device. Alternative filtration surgeries, such as a trabeculectomy, may also be considered, depending on the eye’s overall health and remaining conjunctival tissue.
The long-term goal is finding a new, stable method to protect the optic nerve from further damage. This requires a close partnership with the ophthalmologist, involving frequent follow-up visits and continuous pressure monitoring to prevent glaucoma progression.