Glaucoma is a condition characterized by progressive degeneration of  the optic nerve head.Glaucoma-diagnosis

The symptoms of glaucoma are difficult to recognize until the disease is at an advanced stage.

For this reason, it is of vital importance to have regular eye examinations, especially if a family history of glaucoma exists.

If untreated, glaucoma can cause blindness. Initially peripheral vision is affected but the damage extends if not treated. The damage to the nerve cells cannot be reversed although it is often possible to prevent further damage. The longer the disease is left untreated, the greater the likelihood of damage.

Who is at risk? People over the age of 40 years are far more likely to have glaucoma than younger people. Also, glaucoma tends to run in families so anyone over 40 with a blood relative who has the disease should have their eyes checked on a regular basis, at least every two years

What causes glaucoma?
The exact causes of glaucoma are not known. In some cases the drainage network of the eye may not be formed properly, or may become blocked by natural materials or due to injury; in other cases there is no clear cause.

How can I tell if I have glaucoma?
In most cases a person would not be aware that they had glaucoma. It normally develops over a period of time without any pain or blurring of vision. Glaucoma affects peripheral or side vision first, allowing perfect central vision to be maintained for a long time. Central vision allows us to read and see faces clearly and when this remains normal we may not notice other changes in peripheral vision.

How can the condition be detected?
To diagnose glaucoma the optometrist looks at the nerve fibres at the back of the eye, measures the pressure in the eye with a special instrument called a tonometer and tests the field of vision. These tests are simple and painless. For more information see : eye examination.

It was once believed that the eye pressure was the single cause of the condition, we now know that people with normal eye pressure may also develop the condition.

Treatment?
Eye drops are usually used to treat glaucoma. Surgery may be necessary if there is a blockage in the drainage system and the pressure cannot be reduced. Glaucoma can be very hard to diagnose initially and if your optometrist feels you may be at risk of developing the condition they will often repeat the eye pressure and visual field tests a number of times before deciding whether to refer you or not.

Acute Angle-Closure Glaucoma :
There is a type of glaucoma called Acute Angle-Closure Glaucoma. This has a sudden onset. It can cause the affected eye to be very sore and red, and can produce other symptoms such as noticing haloes around lights, vision loss and headaches. The symptoms may occur in episodes with each episode lasting for a number of hours and causing permanent damage to vision. This type of glaucoma requires emergency treatment by an ophthalmologist.

As early detection is so important, anyone aged 40 or over should have an eye examination every two years. If you are in a higher risk group, you may need more regular checks. Your optometrist will advise you.