How is glaucoma treated?

As was discussed earlier, glaucoma refers to damage to the optic nerve cells. There may be many factors important in causing this, but the biggest factor shown in studies is the level of pressure in the eye. (IntraOcular Pressure, or IOP)

Hence, the main aim of treatment in glaucoma is to lower the eye pressure. Sometimes, the eye pressure may be in the ‘normal’ range of 10-21mmHg, but the nerve continues to deteriorate. In such cases, the eye pressure is lowered further still. Lowering the eye pressure of most glaucoma patients starts with eyedrops (right).

Fortunately there are many medicines available now to reduce eye pressures. If using one does not lower the pressure enough, the doctor may change the eyedrop to a different one, or a second eyedrop may be added. In patients with very high pressures, an oral medicine called Diamox may also be used.

Medicines used to lower the eye pressure either reduce the production of fluid inside the eyeball, or they help the fluid to drain out of the eye more easily. Medicines that do the former include beta blockers such as Timolol, Brimonidine (Alphagan), and Dorzolamide (Trusopt). Others that help with drainage include the prostaglandin analogues Latanoprost (Xalatan), Travaprost (Travatan) and Bimatoprost (Lumigan).

In most cases of glaucoma, long term use of the medication is required. When the medication is stopped, the pressure starts to rise again, and optic nerve damage gets worse with enlargement of blind spots. It is very important therefore, that glaucoma patients do not stop using their eyedrop unless their doctor says it is OK to do so.

As with any medication, glaucoma medicines may have side effects. The most interesting concern the prostaglandin analogues. They do not cause any serious life or sight threatening side effects, but often make the eye redder than normal. This effect can persist for some months, and then often gets better by itself. They also make the eyelashes longer, an effect which has been exploited in the eyelash lengthening treatment called Latisse.

Another cosmetic side effect that is often undesirable is the changing of the iris colour, usually from a lighter blue or green colour to a browner colour, as seen below.

In cases of glaucoma where the front of the eye is narrow, a laser procedure called a laser peripheral iridotomy may be performed (See figure below-the two black dots are small holes in the iris made by a laser; the video below shows the procedure being performed with an Nd:YAG laser). This is a simple procedure performed in the clinic and may take 15 minutes to complete. It helps to improve fluid flow out of the eye despite the narrowness of the anterior chamber.

In some patients, medical or laser treatment fails to lower the eye pressure, necessitating surgery. In the most common operation, a new channel is created for fluid to drain out of the eyeball. This operation is called a ‘trabeculectomy’. To facilitate drainage, sometimes a metal tube (called the ExPRESS shunt) is used as well. In some patients where trabeculectomies have previously been performed but eye pressures have increased again, silicone drainage tubes may be implanted for better fluid flow out of the eye and pressure control.

Glaucoma in the long term

Many people with glaucoma are worried about blindness. However, most glaucoma patients do not become blind. The most important factor is control of the eye pressure, which is achieved either with the use of eyedrops or surgery. If eyedrops are regularly instilled, and eye pressures are well controlled, vision is usually well preserved.

However, patients should realise that damage to the nerve before treatment was started cannot be reversed. The aim in glaucoma treatment is to stabilise the condition, and in most patients vision is maintained for life.