Glaucoma Drainage Device Implant (GDI)
Glaucoma drainage device implants (GDI) involve the placement of a plastic tube inside the eye that drains aqueous fluid to an external reservoir. This fluid is constantly produced and drained out of the inner eye area, and most patients with glaucoma have an imbalance in this system. When there is either too much fluid production or not enough drainage, the pressure inside the eye rises. A common treatment for this is through eye drops, which are designed to lower the eye pressure by improving the fluid production and drainage balance. Similar to many types of glaucoma eye drops, the GDI helps lower eye pressure by allowing excess fluid to be drained and then absorbed by surrounding tissues.
There are many varieties of GDI’s including a valved and a non-valved implant. The implant is shaped like a computer mouse. The body of the implant is placed underneath the conjunctiva, or thin outer tissue of the eye, and sutured to the eye. The tube that extends from the body is then placed into the eye. The entire device is covered by the conjunctiva with the help of a reinforcement patch at the entrance into the eye. Most of the implant will be covered by the eyelid after the surgery.
Candidates for GDI Surgery
GDI’s are most often indicated for those who have undergone a failed trabeculectomy or who have had multiple prior surgeries with no significant scar tissue. It may also be used as primary treatment for those who are prone to scarring such as glaucoma associated with diabetes or uveitis.
The GDI Procedure
The surgery is an outpatient procedure done at either a local surgical center or hospital. It is performed under local anesthesia along with IV sedation supplied by an Anesthesiologist. After the surgery, a patch is placed over the eye to be removed by your surgeon on your first postoperative visit. Frequent postoperative visits along with multiple drops will be required for at least 4-8 weeks. Healing varies among patients, and additional procedures or injections may be required during the postoperative period.
Remember, the goal of the surgery is not to improve vision or cure glaucoma but to lower eye pressure to attempt to slow down the disease progression. Oftentimes, you will be able to stop some of your glaucoma medications, but depending on your type of glaucoma or level of disease, you may require adjunctive treatment with glaucoma medications.
What are the main risks of the GDI?
The most common problem associated with GDI surgery, as with many incisional glaucoma surgeries, is the formation of scar tissue that interferes with the function of the implant. In addition, other complications include blurred vision or decreased vision, worsening of pre-existing cataracts, infection, bleeding, corneal swelling, and double vision. Finally, there is a chance further surgery will be required.
To learn if a GDI is right for your needs, please contact us today to set up an appointment with one of our experienced eye doctors.