Glaucoma Tube Shunt Procedures
What is a tube shunt drainage device?
Glaucoma tube shunts are devices that are implanted in the eye to provide an artificial alternative drainage site for fluid to exit the eye. These devices lower the eye pressure in glaucoma. Most shunt devices look somewhat like a very small computer mouse, with the body of the device being about the size of an average person's fingernail. A tiny tube extends from the body of the device into the anterior chamber, which is the front part of the eye that usually drains fluid from the eye. The device allows excess fluid to drain out through the tube and be absorbed in surrounding tissues. Glaucoma tubes come in many different varieties.
When is a tube shunt procedure indicated?
Glaucoma tube shunt surgery may be needed in patients with glaucoma that is not controlled by medications and/or laser treatment. It may be needed either after failure of previous trabeculectomy surgery (or surgeries) or in certain types of glaucoma where traditional trabeculectomy surgery would almost certainly fail. Examples of such patients are those with neovascular glaucoma, and patients who have corneal transplants.
What is done during the tube shunt procedure?
Usually, a small incision is made near the top of eye underneath the conjunctiva, the thin outer covering of the eye. The body of the device lies over the top of the eye but underneath the outer covering of the eye. After the body of the device is sutured in place, the tube, which extends from the body of the device, is inserted into the eye's anterior chamber. Although the device is sutured onto the top of the eye, it is completely covered by the eye's white outer covering, the conjunctiva. Most, if not all, of the device will not be visible behind the upper eyelid after the surgery.
What should I expect if I have a tube shunt procedure?
The procedure is done under local anesthesia in the operating room. First, eye drops are used to numb the eye. Then, your eye will be cleaned and a sterile drape will be put over your face and body, leaving only your eye uncovered. This keeps the area of the operation clean and sterile. Your eye will be held open by a "lid speculum," so you will not blink during the surgery. Some surgeons may also give your sedating medications through an IV (intravenous) line to keep you completely comfortable. After the surgery is over, a patch and shield will be placed over your eye. This will be removed the day after surgery on your first post-operative visit. You should expect to be seen frequently by your surgeon until the eye completely heals. For many people, this may take six to eight weeks. During this time, you will be taking frequent and multiple eye drops. The postoperative care varies greatly and may include suture removal and/or other minor procedures to maximize the outcome of the surgery. During this time, you will need to restrict yourself from strenuous activities.
Will my glaucoma be cured with the glaucoma tube device?
No. Any vision that is already lost prior to the surgery, in general, 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.
Can I stop my eye drops after the surgery?
You will definitely need eye drops for two or more months after the surgery. Some people do not have to take eye drops after that period. Many people will eventually need some glaucoma eye drops to keep their pressure under control. 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. Operations are not done unless the benefits outweigh the risks. Risks include, but are not limited to, bleeding, infection, hypotony (very low 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 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.