What is glaucoma? Glaucoma is a chronic progressive disease that can cause blindness if not treated in time. This happens when the nerve in the eye cannot handle the pressure in the eye and therefore sustains permanent damage.Normal pressure in the eye is usually between 12-21 mmHg. But a high pressure alone does not necessarily mean that you have glaucoma.Some people’s nerves can handle a pressure higher than 21 mmHg without being damaged, whilst others show damage even if their pressures are normal.That is why it is important to visit your ophthalmologist on a regular basis, who can measure the pressure and do special tests to determine whether your eye nerves have any damage. These tests may include visual fields (which determine your peri-pheral vision), and an HRT (which measures the thickness of the retinal nerve fibre layer). These tests are also used to monitor the progression of the condition.There are different types of glaucoma, each with their own causes, symptoms and treatment modalities.This article concentrates on the type that occurs most commonly, namely primary open angle glaucoma (POAG). Who can get glaucoma? Anybody can develop glaucoma, but certain people have a higher risk than others. This includes those with a family history of glaucoma, as well as everybody over the age of 40.Patients who suffer from diabetes or are near-sighted also have an increased risk.What are the symptoms?The patient does not experience any symptoms in the beginning stages of POAG. Vision is normal and there is no pain. In this type of glaucoma, the patient slowly loses vision. The visual loss starts on the sides and gradually spreads to involve the centre vision, which leads to tunnel vision and eventual blindness. What is the treatment? The damage that has been done to the nerve is permanent and irreversible. With the correct treatment, however, one can delay any further loss of vision.The first line of treatment is eye drops. These should be used on a daily basis to control the pressure. There are different types of drops available and your ophthalmologist will determine which one is best for your eyes. It may be necessary to use more than one type of eye drop. If the drops alone do not control your pressure adequately, there are other options available (for example laser treatment or surgery). How should I use my eye drops? It is imperative to use the eye drops exactly as prescribed. Do not miss a dose, and try to use it approximately the same time each day.Using the drops more often than prescribed will not decrease the pressure further. Always use the drops on the day of your follow-up visits, so that your ophthalmologist can see whether it is working. If you see that your drops are almost finished, make sure that you go to your pharmacy in time. How can I prevent glaucoma? Unfortunately, there is nothing you can do to prevent this. Visiting your ophthalmologist regularly can help to detect glaucoma early so that treatment can be started in order to limit further loss of vision.To control glaucoma successfully, you need to work closely with your ophthalmologist. Your ophthalmologist will monitor your pressure and the function of your nerve on a regular basis and adjust your treatment accordingly. It is your responsibility to use your drops as prescribed and to strictly adhere to your follow-up appointments.It is recommended that everyone over the age of 40 visit an ophthalmologist to screen for glaucoma. Queries can be directed to the ophthalmologists at the Horizon Eye Care Centre. Article written by Dr Karen Conradie, MBChB, MMed (Ophth), FC Ophth (SA), ophthalmologist.