Trabeculectomy
The Procedure. Filtration surgery has been used for more than 100 years with only minor modifications. It employs conventional surgical techniques known as full-thickness filtering surgery or guarded filtering surgery (trabeculectomy).
- The surgeon creates a sclerostomy , a passage in the sclera (the white part of the eye) for draining excess eye fluid.
- A flap is created that allows fluid to escape but which does not deflate the eyeball.
- The surgeon may also remove a tiny piece of the iris (called an iridectomy ) so that fluid can flow backward into the eye.
- A small bubble called a bleb nearly always forms over the opening, which is a sign that fluid is draining out. Although surgeons aim for a thick bleb, which poses less risk than a thin one for later leakage, paradoxically the ideal operation would have no bleb at all.
The procedure has a high success rate. About 50% of patients no longer need medication after surgery. Thirty-five to 40% of those who still need medication have better control of their glaucoma.