During a trabeculectomy, a small piece of tissue is removed to create a new channel for the fluid to drain from the eye. This fluid will drain between the eye tissue layers and create a blister-like “filtration bleb.” Trabeculectomy surgery is performed one eye at a time, usually spaced four to six weeks apart.
This procedure is about 60 to 80 percent effective at lowering eye pressure. If the new drainage opening narrows, a second operation may be needed. Conventional surgery works best if you have not had previous eye surgery, such as a cataract operation.