Below is a narrated animation about trabeculectomy procedure for glaucoma. Click here to license this video on Alila Medical Media website.

Trabeculectomy, also called Filtration Surgery, is a surgical procedure performed for treatment of glaucoma. The treatment involves removing part of the trabecular meshwork and creating a new escape route for the aqueous humor. When successful, it allows the aqueous fluid to drain from the eye into an area ( called a bleb) underneath the conjunctiva where it is subsequently absorbed by the body’s circulatory system or filtered into tears.

Fig. 1: Trabeculectomy (on top) compared to normal anatomy (bottom). Click on image to see it on Alila Medical Media website where the image is also available for licensing (together with other related images and videos).

 

 

 

 

In this procedure:

–          A conjunctival pocket is created and maybe treated with Mitomycin or other antimetabolites for a few minutes. These drugs are used to prevent scarring of the operation site. Scarring, if occurs, may clog the new drainage canal, and is therefore the major reason the procedure may fail.

–          A half thickness flap is then made in the sclera and is dissected all the way to the clear cornea. (step 1 in Fig.2)

–          A block of scleral tissue including part of the trabecular meshwork and Schlemm’s canal is then removed to make a hole into the anterior chamber of the eye. (step 2 in Fig. 2)

–          As the iris may plug up this hole from the inside, a piece of the iris maybe removed at this time. This is called iridectomy. (step 2 in Fig. 2)

–          The scleral flap is then sutured loosely back in place (step 3 in Fig. 2). These sutures can be released gradually during a couple of weeks after surgery. This allows adjustment of the aqueous flow in order to achieve target pressure and to avoid the complication of having a too low intraocular pressure.

–          The conjunctiva is sewn back in place to cover the area.

Fig. 2: Steps of Trabeculectomy procedure, anterior view. Click on image to see it on Alila Medical Media website where the image is also available for licensing (together with other related images and videos).

 

 

After surgery, aqueous humor drains into a filtering area called a “bleb” under the conjunctiva. Since the surgery is usually performed near the top of the eye, the bleb can easily be concealed behind the upper eyelid.