Trabeculectomy (Filtration Surgery) for Glaucoma:

The fluid inside the eye, known as aqueous humor, drains through the trapdoor into a small reservoir or blister just below the eye’s surface, hidden by the eyelid.

The trapdoor is sutured (sewn) to prevent the aqueous humor from draining too quickly.

By draining the aqueous humor, the pressure on the optic nerve is reduced, and more damage and loss of vision are prevented or delayed. Controlling eye pressure with a trabeculectomy does not restore vision.

Glaucoma is often caused by high pressure inside the eye. Trabeculectomy reduces eye pressure by draining aqueous humor from the eye.

What is the appearance of the eye after a trabeculectomy?

Initially, the eye is red and swollen to a variable degree after surgery. The eyelid may also partially fall. This usually resolves over weeks to months. After the trabeculectomy operation, the drainage bleb is not typically visible to the naked eye. The blister can be seen if the patient looks in the mirror and lifts the upper eyelid.

After surgery, most patients do not feel any sensation of the presence of the drainage bleb. Rarely are patients aware of the drainage bleb.

The medication before surgery

Before undergoing surgery, patients should continue with all drops and tablets according to their regular treatment regimen until the morning of the operation. Medicines should also be continued to dilute the blood, such as aspirin, warfarin, and clopidogrel.


However, the doctor may request the suspension of anticoagulant medications before surgery to ensure that the correct therapeutic range is met.

If patients choose to have surgery performed under general anesthesia, a preoperative evaluation of their available health status will be carried out just before the surgery. Underlying medical conditions, including heart disease, uncontrolled high blood pressure, and diabetes, are treated before a scheduled surgery.