Glaucoma is a common and usually chronic condition that can destroy your eyesight if it is not controlled. Of the four main types of glaucoma, only one, congenital glaucoma, affects children and is usually due to a problem with eye development. The other three types of glaucoma all affect adults, usually from middle age onwards.
The raised pressure inside the eyeball that is the main cause of glaucoma often causes no symptoms but if it is not diagnosed early enough, the increase in pressure causes progressive damage to the optic nerve as it leaves the back of the eye. This damage is permanent and any eyesight that is lost can never be regained. If the problem is recognised early, various glaucoma treatments are available to reduce the intraocular pressure and so prevent damage to the delicate structures of the eye.
Types of glaucoma
Glaucoma treatments depend on the type of disease that you have. Glaucoma is described using some strange-sounding terminology, so it helps to first understand how glaucoma is classified:
Congenital glaucoma: this is caused by an inherited condition, a developmental problem or a difficult birth and is present in newborn babies. Specialised treatment, often involving corrective surgery, is done by a paediatric team.
Chronic open-angle glaucoma usually develops very gradually and there is still some drainage of fluid from the eye. Glaucoma treatment therefore tends to focus on drugs delivered directly to the eye in the form of drops. In cases that do not respond, laser treatment and surgery are also available.
Chronic angle-closure glaucoma also develops slowly over time but acute angle-closure glaucoma can come on very quickly, with eye pressures increasing dramatically and causing eye pain. Treatment options are similar to open-angle glaucoma, but the situation is somewhat more urgent as there is little drainage of eye fluid and damage can happen more quickly. Immediate treatment is required for the acute form to prevent imminent loss of sight.
Secondary glaucoma (which can be open-angle or angle-closure) develops as a result of another disease, such as diabetes, or because of an eye infection, or because of injury to the eye. Glaucoma treatment will be given alongside therapy for the underlying cause.
All chronic forms of glaucoma that are detected early can usually be controlled with eye drops. These contain drugs that either make fluid drain from the eye faster, or they reduce the volume of fluid that is produced inside the eyeball. The main classes of drug that your doctor or ophthalmologist might recommend include:
Beta-blockers, such as metipranolol and betaxolol hydrochloride. These drugs seem to decrease the amount of aqueous humour that is produced. In the normal eye, this fluid is generated continuously but cutting its production down can help the eye keep up with draining excess fluid away.
Carbonic anhydrase inhibitors, such as dorzolamide. Again, these drugs reduce the amount of fluid that is released within the eye.
Prostaglandin analogues, such as latanoprost. Prostaglandin-like drugs increase the rate of drainage, thus reducing eye pressure. They do not affect fluid production.
Sympathomimetics, such as brimonidine tartrate. These offer a double-whammy glaucoma treatment as they increase drainage and reduce fluid production.
All classes of drug that are useful in glaucoma will have some side effects, often related to the eye itself, such as irritation, redness or stinging, but they can also affect the rest of the body. Eye drops containing beta-blockers, for example, cannot be taken if you have asthma or heart problems, as the tiny amounts of the drug that get into your bloodstream can make your other health problems worse.
All can be very effective glaucoma treatments and there is a huge choice of individual drugs in each class. Your doctor may try several before you find the eye drops that are effective enough to bring your intraocular pressure down, but have no adverse effects on your eyes or on your general health.
If your glaucoma does not respond very well to drops, laser treatment is then a second-line option. Two types of laser surgery are effective glaucoma treatments:
Laser trabeculoplasty: a laser is used to open up channels in the network of drainage tubes in your eye. This is a minor operation that is done under local anaesthetic. The laser light enters through your pupil and makes small holes in the drainage tissue. Following the laser treatment, your glaucoma should be stable, as fluid will immediately be able to drain out of the eye much more freely.
Cyclodiode laser surgery: this is used to destroy some of the cells that produce the fluid that fills the eyeball. With less fluid produced, your drainage system should be able to cope better.
Surgery is available in the most severe cases and where resistance to glaucoma treatment is a problem. Three main surgical procedures can be used to reduce eye pressure and to prevent it from building again:
Implantation of an aqueous shunt: a small tube is implanted into the eye to allow fluid to drain out.
Deep sclerectomy: this also involves putting in place an implant but, in this case, it is a smaller tube that widens the existing network of drainage tubes.
Viscocanalostomy: a small portion of the white of the eye is removed, which allows the fluid to seep out of the eyeball.
Is the treatment effective?
Far fewer cases of blindness due to glaucoma now occur in the UK compared to the days before eye pressure could be detected. The combination of accurate diagnosis and prompt treatment means that overall management of this condition is highly successful. No one glaucoma treatment is perfect but the range of options available means that there will be an effective treatment for most people.