I will discuss chronic glaucoma which is a very common potentially serious eye condition. Glaucoma is the second most common cause of blindness in the world, with cataracts being the most common. The important point to realise is that glaucoma blindness is preventable. Again, this article is not meant to replace the advice of your GP or eye specialist.
What is it?
Glaucoma is a term describing slow damage to the optic nerve with a resulting specific pattern of vision loss. It is mostly caused by raised eye pressure but very rarely a subtype of glaucoma occurs when the eye pressure does not rise above the normal range. This is called normal-tension glaucoma. Usually however the eye aqueous (water) pressure slowly builds over years resulting in damage to the optic nerve. This pressure rise in chronic glaucoma is normally not uncomfortable for the patient. Very slowly the optic nerve starts to lose peripheral nerve fibres. This damage results in the specific pattern of peripheral visual loss. That’s why we are told that glaucoma causes “tunnel vision”. The damage is so slow that most people do not realise that they are losing peripheral sight. So with a raised pressure that is not sore and with very slow loss of peripheral vision it is understandable that most people may not be aware that they have the disease. This is why screening for the raised pressure is vital in the community especially in those over the age of 40. All optometrists can measure eye pressure and if they are concerned then they should refer to an ophthalmologist who will check the pressure and look for other signs and start treatment if necessary. If left undetected and untreated the condition will worsen gradually and the visual loss will start encroaching on the central vision, which means that total blindness will follow. People at increased risk of glaucoma are those with a family history of it, those on long-term steroid use and those who have had previous eye injury.
What can be done?
The most important intervention is detection. This is just one of the reasons why all people should have their eyes checked at least every 2 years. Once detected, therapy can be commenced. There are fortunately many extremely good and safe eye-drops available to combat glaucoma. These all work to decrease the intra-ocular pressure (eye pressure) for the patient. It is imperative to understand that treatment should be ongoing with regular review by your ophthalmologist to confirm adequate pressure reduction and to confirm that the glaucoma is not progressive. Glaucoma, unlike say an infection, can’t be treated with a single course of medicine. The patient will need to use the eye-drops for life but with once-a-day eye-drops now available it is a small price to pay to prevent blindness. Occasionally in some, despite regular use of drops, the glaucoma progresses and requires further treatment. This can be done with a special type of laser for the eye or surgery. Both generally work very well but sometimes drops will still be needed afterwards.
So, with appropriate early detection, evaluation and treatment the vast majority of glaucoma patients will not suffer unduly.