Trabeculectomy: Glaucoma Filtration Surgery
Trabeculectomy is a glaucoma surgery which is generally recommended for patients with glaucoma that continues to progress despite use of medications and/or laser reatments. In some cases, trabeculectomy surgery maybe recommended prior to trying medical or laser treatment. These decisions vary depending on the type of glaucoma, the stage of glaucoma, as well as other factors. Sometimes this surgery can be combined with cataract surgery.
A new drainage site is created to facilitate drainage of fluid FROM the eye. Instead of draining into the normal drainage site of the eye (the trabecular meshwork), the fluid is drained into a new space (a “bleb”) that is completely covered by the white outer covering (the conjunctiva) of the eye. This will lower the eye pressure.
The main reason trabeculectomy surgery fails is that the drainage site can scar and therefore close up. Antimetabolites, or medications that prevent scarring, can be used to increase the success rate of trabeculectomy surgery in some patients. Since antimetabolites can increase the complication rate of surgery, it is generally eserved for patients that may be at increased risk for trabeculectomy failure. Mitomycin C (MMC) is most commonly used in this procedure.
Trabeculectomy is done under local anesthesia in the operating room. Some surgeons may also give the patient sedating medications through an IV (intravenous) line to keep him/her completely comfortable. After the surgery is over, a patch and shield will be placed over the surgical eye. This will be removed the day after surgery on the first post-operative visit in the doctor’s office. The patient should expect to be seen quite frequently by your surgeon until the eye completely heals. For many people, this may be even for up to 2-3 months. During this time, the patient will be taking frequent and multiple eye drops. In some case the patient may need either removal of sutures, a laser procedure to cut some sutures, injections of supplemental medications, or other office procedures to modulate and control the healing process. This will maximize the outcome of the surgery. The postoperative care will vary from patient to patient, and your doctor may not be able to predict what will need to be done after the surgery. The patient will also be restricted from strenuous activities during the healing process.
Any vision that is already lost prior to the surgery, in general, will not return. Trabeculectomy surgery only lowers patient’s eye pressure. By lowering the eye pressure, the goal is to either stop or slow down the loss of vision. In some case this goal is not possible.
All eye surgery has some risks. Risks include, but are not limited to, bleeding, infection, swelling, scarring, retinal detachment, a droopy eyelid, double vision, loss of vision or even loss of the eye. In general, many of these risks are not common, however, you may want to discuss the benefits and risks with your surgeon should you have any further questions.
Glaucoma Tube Shunt Procedures
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 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.
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. Click here to learn more about Ahmed Valve tube shunt device.
Lumenis Selective Laser Trabeculoplasty (SLT) for the reduction of intraocular pressure (IOP) in patients with open-angle glaucoma.
SLT (Selective Laser Trabeculoplasty) is a safe and simple in-office laser treatment that effectively reduces eye pressure for most patients with glaucoma. The SLT mechanism of effect does not rely on medicines, instead, it uses an advanced laser system to target only specific cells of the eye—those containing melanin, a natural pigment. This allows for only these cells to be affected, leaving surrounding tissue intact. As a result, your body’s own healing response helps lower the pressure in your eye.
Angle closure involved the lens coming too close to the iris and blocking the passage of fluid into the front of the eye, where it drains into the circulation. Relief of the relative pupillary block allows the iris to move back and the anterior chamber drainage angle to open, allowing escape of aqueous humor and lowering of the intraocular pressure. This is now commonly and simply done by fabricating a small hole in the iris with laser (laser iridotomy), which provides another route for fluid to enter the front of the eye. This equalizes the pressure between the posterior and anterior chambers and allows the iris to fall back to its normal anatomic position and away from the trabecular surface.