OPHTHALMOLOGY

Q: I have primary open angle glaucoma and recently had a trabeculectomy performed on my right eye. My eye doctor told me that if the bleb created during the procedure fails, I may need a bleb needling procedure. What is a bleb, a bleb needling, and when is this procedure called for? A: A trabeculectomy is a surgery used to treat primary open angle glaucoma when eye drops or laser treatment or both have failed to reduce the intraocular pressure (IOP) enough to prevent damage to a person’s eyesight.

The purpose of a trabeculectomy is to create a new drainage opening so that the fluid from inside the eye, the aqueous humor, can be directed to the outside of the eye thus reducing IOP.

During a trabeculectomy, a piece of tissue in the drainage angle is removed to create an opening. As fluid flows through this new drain opening, the scleral and conjunctival tissues over the opening rise to form a little blister or bubble called a bleb. The bleb is located under the upper eyelid and is where the sclera, or the white part of the eye, joins the cornea, or clear outer shell of the eye. The bleb is very small and can usually be seen only with a microscope.

Sometimes blebs fail. The most common reason for this is the body’s own healing process which creates scar tissue around the new opening that can close up the drainage passage that was created. As a result, IOP may once again begin to increase because fluid is not flowing out of the bleb as it did before.

When a bleb fails, a brief procedure called a bleb needling or bleb revision as it is also known, to open the scarred-over area to restore drainage. A bleb needing is a safe, effective method of reviving a failed bleb. Your eye doctor may recommend a bleb needling to avoid using more eye drops for IOP control, or to avoid additional glaucoma surgery.

Bleb needlings are usually performed in the doctor’s office and take 5-15 minutes. The success rate of a bleb needling varies and factors affecting the outcome include the time period since the initial trabeculectomy and the degree of scarring that has occurred.

This procedure can and sometimes needs to be performed more than once during postsurgery healing. Many eye doctors consider a bleb needling as an appropriate step in the management of glaucoma patients who have developed scarring following a trabeculectomy. The risks are considered minimal and the chance of recovering drainage function is generally good.