Glaucoma - Surgery

Laser Trabeculoplasty

The Procedure. Laser trabeculoplasty involves the following steps:

The procedure employs an instrument, usually a YAG laser, to burn 80 to 100 tiny holes in the drainage area.
A tiny scar forms, which increases fluid outflow.
The procedure takes 15 minutes, causes almost no discomfort, and has very few complications.

In a 2-year study, laser surgery of the trabecular meshwork reduced pressure by one third in 70 -97% of patients. Patients still need to take anti-glaucoma eyedrop medications every day.

Laser surgery is not a cure. Within 2 to 5 years, about half of patients need either additional surgery or new medications.

Complications. In about 35% of patients, pressure increases after surgery. In most cases it is temporary, but rarely the increased pressure is permanent and vision loss can occur. Use of the drug apraclonidine (Iopidine) or pilocarpine can help prevent this elevated pressure. About a third of patients also develop adhesive-like substances called peripheral anterior synechiae that cause the iris to stick to part of the cornea.

Drainage Implants

Implants may be used to drain fluid in certain cases, such as if glaucoma is not responsive to any standard procedure or is caused by certain conditions.

Candidates. Success rates are highest (75% pressure control over 5 to 7 years) in appropriate patients. Drainage implants may be useful in the following conditions:

Glaucoma caused by swelling in the iris
Glaucoma caused by abnormal vessel formations
Iridocorneal endothelial (ICE) syndrome

The Procedure. In general the procedure is as follows:

An implant, most commonly a 1/2 inch silicone tube, is inserted into the eye's front chamber (anterior). The Molteno implant used with mitomycin C is currently the most effective approach, with reported success rates of 80%. Other implants, such as the Ahmed implant, may have fewer complications.
The tube drains the fluid onto a tiny plate that is sewn to the side of the eye.
Fluid collects on the plate and then is absorbed by the tissues in the eye.

Complications. Complications include the following:

Hypotony (very low eye pressure) is a serious complication that has been reduced using better techniques and improved implants.
Cataracts, detached retina, breakdown of the cornea, and bleeding are potentially significant complications.
There is also a risk for eye movement disorders, such as strabismus (crossed eyes) or diplopia (double-vision).

The implant often becomes blocked and repeated operations are needed. Some investigators are studying the use of a drugcalled tissue plasminogen activator (tPA) to open up tubes that have been blocked by blood or blood factors. (This so-called clot-busting drug is normally used to break up blood clots during heart attacks.) In one 2002 study, tPA prevented such blocks in 89% of eyes. Unfortunately, significant complications rates were high (11%).