Glaucoma is the name for a group of eye conditions in which the optic nerve (the nerve at the back of the eye) is damaged – often due to raised pressure within the eye. This leads to a reduction in the field of vision and the ability to see clearly. In most cases glaucoma sufferers will experience no symptoms until significant damage has occurred. Glaucoma affects people of all ages and is the second leading cause of blindness in the world.
Types of glaucoma
There are four main types of glaucoma:
- Chronic Open-Angle Glaucoma – The most common vein of the disease, this develops over time and very slowly. Symptoms generally go unnoticed.
- Primary Angle-Closure Glaucoma – This is the rarest form of glaucoma. It can occur slowly or suddenly with a sudden, painful build up of pressure in the eye.
- Secondary Glaucoma – Typically the result of an eye injury or trauma brought on by another eye condition.
- Developmental Glaucoma – One of the most serious types of glaucoma, but it’s very rare. This occurs in very young children and is caused by an abnormality in the eye.
Who is at risk of glaucoma?
Although anyone can develop glaucoma, there are certain groups of people who are at greater risk. It’s much more common in people aged 40 and over, and the risk increases with every decade of life. Those with a family history of glaucoma are also more likely to develop the condition, as well as those from a certain ethnic group (i.e. African-Caribbean people). People who are diabetic or very short sighted are also more likely to develop glaucoma.
Whatever your risk, it’s crucial that you have regular eye tests to ensure any abnormalities which could signify glaucoma can be spotted as early as possible. To aid detection of glaucoma, the College of Optometrists recommends an eye examination every two years, or more frequently if there is a family history of the condition.
How do optometrists test for glaucoma?
Most new cases of glaucoma are identified through referrals from optometrists whose training equips them to recognise the early signs of the disease. There are three main eye tests that may be carried out by an optometrist to check for glaucoma:
- Ophthalmoscopy – This involves checking the appearance of the optic disc (where the optic nerve joins the eye) using an ophthalmoscope, a special torch for looking into the eyes.
- Visual field assessment – Optometrists can test the field of vision using small points of light to check for blind spots.
- Tonometry – This involves measuring the pressure within the eye; either using an instrument that emits a small puff of air onto the surface of the eye, or placing a probe against the eye after it has been numbed with anaesthetic drops.
Other instruments are now available for detecting and monitoring glaucoma but these are the most commonly used tests. At Eyesite we offer a range of eye examination services to our patients, which enables our optometrists to identify early signs of a range of eye disorders, including glaucoma.
Patients at Eyesite are able to choose our specialist Optical Coherence Tomography (OCT) scan which is specifically designed to provide a highly detailed cross-sectional image of the back of the eye. It is one of the most advanced forms of eye tests available that can detect early signs of glaucoma.
Working in a similar way to an ultrasound, the OCT eye test takes 128 different scans of the back of the eye to create a 3D view of the optic nerve. Our optometrists – who are experts in diagnosing common eye disorders such as glaucoma – can use these images to identify any abnormalities that may suggest there is a build-up of pressure in the eye. This is a vital clue that glaucoma could be present, and that treatment needs to be provided immediately.
If your optometrist suspects glaucoma following a routine eye test, they may advise you to be referred to a GP or hospital for treatment. If detected early enough, in most cases glaucoma can be effectively treated, and blindness can be prevented. Typically, eye drops to reduce the pressure in the eye will be prescribed, although some sufferers may need an operation. The type of treatment provided typically depends on type and severity of glaucoma. Once treatment is underway, you may be referred back to your optometrist for monitoring.
Glaucoma sufferers and certain close relatives are entitled to a free eye examination provided by the NHS. Those diagnosed as being at risk of developing glaucoma are also eligible.