When is a tube shunt procedure indicated?
Glaucoma drainage implant surgery, sometimes referred to as a tube shunt, may be needed in patients with glaucoma that is not controlled by medications and/or laser treatment. It may be needed either as primary glaucoma surgery in certain types of glaucoma or after failure of trabeculectomy surgery.
In trabeculectomy surgery, a tiny drainage hole is made in the sclera (the white part of the eye). This opening allows fluid to drain out of the eye under the delicate membrane covering the eyeball known as the conjunctiva. The fluid does not spill out of the eye but is simply re-routed to another area of the eye where it is absorbed by the internal blood vessels. Locally-applied medications or injections may be used to help keep the hole open.
With tube shunt surgery, most of the device is positioned on the outside of the eye under the conjunctiva (eye tissue), usually underneath the upper eyelid. The tube portion of the device is carefully inserted into the front chamber of the eye, typically just in front of the iris (colored part of the eye). The fluid drains through the tube, into the area around the back end of the reservoir of the shunt. The fluid collects here and is reabsorbed. One cannot feel the implant and it is usually not visible unless one lifts the eyelid or opens the eye very widely.
What should I expect if I have a tube shunt procedure?
The procedure is done under local anesthesia in the operating room. After some eye drops are put in the eye and after the eye is numbed and cleaned, a sterile drape will be placed over your face and body and will leave only your eye uncovered. Your eye will be held open by a small spring so you do not have to worry about blinking during the surgery. The anesthesia team will give you sedating medications through an IV (intravenous) line to keep you comfortable. After the surgery is over, a patch and shield will be placed over your eye. This will be removed the day after surgery. You should expect to be seen frequently by your surgeon until the eye completely heals. For many people, this may take 6 to 8 weeks. During this time, you will be taking frequent and multiple eye drops to prevent infection and promote healing.
Will my glaucoma be cured with the glaucoma tube device?
No; glaucoma can not be “cured” but can be controlled by lowering the eye pressure. Any vision that is already lost prior to the surgery will not return. Tube shunt surgery only lowers your eye pressure. By lowering the eye pressure, the goal is to either stop or slow down your loss of vision. Sometimes this goal is not possible. Most people will need some glaucoma eye drops to keep their pressure under control despite the surgery. In some cases, people will be taking fewer eye drops than they were before the surgery. The need for eye drops after tube shunt surgery varies greatly and is determined by your type of glaucoma and the rate it is progressing.
What are some risks for tube shunt surgery?
All eye surgery has some risks. Any operation is not done unless the benefits outweigh the risks. Risks include, but are not limited to, bleeding, infection, hypotony (too low an eye pressure), scarring, swelling, retinal detachment, droopy eyelid, double vision, loss of vision, or even loss of the eye. Sometimes the tube fails and needs to be replaced. In other cases, the tube may function to some degree but not well enough to lower the eye pressure adequately. In those cases, additional surgical procedures are sometimes needed to further control the eye pressure. In general, many of the risks are not common, however you may want to discuss the benefits and risks with your surgeon should you have any further questions.