In open-angle glaucoma, aqueous humor, the fluid that normally flows in and out of the eye, has difficulty leaving through the eye's sponge-like drainage system, the trabecular meshwork. When this occurs, pressure within the eye, called intraocular pressure, builds up and may damage the optic nerve and lead to vision loss. Medications, laser surgery, or other glaucoma surgeries may be used to lower and control the eye pressure.
When is surgery necessary?
When medications or laser treatment cannot lower eye pressure caused by glaucoma, surgery is usually recommended. Of the possible procedures, glaucoma filtration surgery, also called trabeculectomy, is the most common.
How is Trabeculectomy done?
A small flap is made in the sclera (or white) of the eye. A filtration bleb, or reservoir, is created under the conjunctiva, the thin, clear coating covering the sclera. The aqueous humor inside the eye can drain through the flap and collect in the bleb, where it is then absorbed into the lymph and blood vessels around the eye.
After the bleb is carefully constructed, the incision is closed with tiny stitches. Some of these stitches may be removed or cut with a laser after surgery to increase fluid drainage.
Drugs to reduce scarring are often applied during and after surgery.
The bleb looks like a bump or blister on the with of the eye, but is usually hidden by the upper eyelid.
Fluid drains from the inside of the eye into the bleb.
What can you expect if you have surgery?
► Before Surgery
You will continue to use your glaucoma medications until just prior to surgery. If you take aspirin or any aspirin-containing products, these should be discontinued 10-14 days prior to your eye surgery.
► The Day of Surgery
A trabeculectomy is done in an outpatient operating room with a local anesthetic to prevent discomfort during the operation. You may also be given a sedative to relax you. General anesthesia is rarely necessary. The procedure is usually performed in less than an hour, but it may take longer if you have had a previous eye surgery, or if your eye is inflamed or abnormal blood vessels are present.
► After Surgery
Postoperative care is as important to the long-term success of the operation as the surgery itself. In follow-up appointments, your ophthalmologist (Eye M.D.) will examine the filtering bleb, the external appearance of the eye, your eye pressure, and the back of your eye. You should avoid lifting, bending, or straining after surgery, until your eye pressure stabilizes.
Pain is unusual after surgery, although your eye may feel tender and sensitive. A non-aspirin pain reliever is usually sufficient to treat any discomfort. Sudden, severe, or deep-seated pain, especially if it is associated with loss of vision, should be reported to your ophthalmologist immediately.
Eye pressure is adequately controlled in three out of four people. Although follow-up visits are still necessary, many people no longer need to use eye drops. However, if the opening closes or too much fluid drains from the eye, additional surgery may be necessary.
What will my vision be like?
Vision may fluctuate daily after surgery. Generally your vision is blurry for several weeks. There may or may not be a change in your glasses prescription after surgery.
If a cataract is present or another complication exists, vision may not return to what it was before surgery. Surgery cannot restore vision already lost from glaucoma.
As with all surgeries, there are risks associated with a trabeculectomy. One of the most common complications is scarring. Other complications include:
► loss of vision