Trabeculectomy

The most common surgical treatment for glaucoma is a procedure called a trabeculectomy. This is usually done as a day case so admission to hospital is not necessary. The idea is to unclog the build-up of fluid in the eye caused by glaucoma (intraocular pressure). Trabeculectomy is usually done when medication does not work and glaucoma is likely to progress and eventually cause blindness.

The eye has a tough outer wall (sclera, or white of the eye), which is covered by a thinner skin (conjunctiva). In a trabeculectomy, the surgeon creates a flap over a small hole in the sclera. This flap forms a passage to drain the fluid in the eye (aqueous humour). This procedure deals with the obstruction of the fluid in the eye and the pressure that this causes.

As the fluid drains from the new opening, the tissue over the opening rises to form a small blister or bubble called a bleb. The bleb is located where the sclera joins the iris (coloured part of the eye). During follow-up care, the surgeon will examine the bleb to make sure that the fluid is still draining out of the new opening.

After surgery

After surgery, antibiotics may be applied to the eye. Usually the eyelid is taped shut and an eye shield used. The eye shield may be used at bedtime for several weeks after.

It is recommended that after the procedure, activities that might jar the eye should be avoided. This include bending, lifting etc. It can also include straining to pass stools and if there are difficulties in this regard, laxatives may be useful.

There may be mild discomfort after a trabeculectomy. However, more severe pain may be a sign of complications, so in this case, the doctor’s advice should be sought.

Possible side effects

The most common problem after a trabulectomy is scarring of the opening. If this occurs, it may impede drainage of the eye and the proper functioning of the bleb. Usually there are treatments given during surgery to prevent scarring. Some can be given after the operation if problems arise. If bleb problems do occur, a plastic drainage device may be place in the eye to help drain fluid.

Severe blurring of the vision for several weeks is quite common. An infection in the eye is also a possibility. A very slight droop of the eyelid is common but a more pronounced droop can be a possible side effect. Your doctor will give you advice about what to expect.

Viscocanalostomy

This is where the surgeon removes a block of the sclera to leave a thin membrane through which the eye fluid drains. While there are less complications likely, the reduction of intraocular pressure may not be as great.

The procedure gets its name because during the surgery a thick fluid (visco-elastic) is injected into an area called Schlemm’s canal. The eye fluid drains way through Schlemm’s canal or under the conjunctiva.

Deep sclerectomy

This is similar to viscocanalostomy. It is performed with the insertion of a collagen implant under the scleral flap to improve the draining of aqueous humour under the conjuntiva.

Tube or valve operations

In this procedure, a small plastic tube is placed in the eye. This allows the eye fluid to drain into a reservoir under the conjunctiva. This is hidden under the top eyelid. The fluid is absorbed from the reservoir into the bloodstream.

Iridectomy

This is used in the treatment of closed angle glaucoma. A small piece of the iris is removed to bypass the fluid blockage.

Laser treatments

There are a number of laser treatments also available:

• Cyclodiode
• Iridoplasty
• Iridotomy
• Peripheral laser iridoplasty
• Pupilloplasty
• Trabeculoplasty.

Future developments

In 2010, a Belfast women was the first person in the UK and Ireland to have a small device implanted in her eye to treat glaucoma. A tiny piece of titanium, called the iStent, was used. This drains fluid away to lower eye pressure from the sensitive part of the eye, which causes glaucoma.