Glaucoma is one of the leading causes of preventable blindness in Ireland. There are no symptoms in its early stages, but a thorough eye exam can detect the signs of glaucoma before you realise there is a problem.
What is glaucoma?
Glaucoma is an eye condition that causes damage to the optic nerve, which transmits images to the brain. The eye needs a certain amount of pressure to maintain shape and size. However, increased fluid can put pressure on the optic nerve and cause damage.
If glaucoma is not treated, damage can progress, causing a loss of peripheral (or ‘side’) vision and may eventually lead to complete sight loss.
The eye produces a watery fluid called aqueous humour. Normally the fluid produced is balanced by fluid draining out, but if too much fluid is produced or if the drainage channels become blocked, then your eye pressure will rise. Too much pressure can damage the optic nerve.
Glaucoma has no symptoms in the early stages so you may not notice any pain or noticeable change in your vision. 40% of your optic nerve can be damaged before you notice any loss of vision. That is why it is so important to have regular eye exams. A routine eye exam could pick up glaucoma before you notice any changes to your vision, and treatment may prevent any deterioration.
Glaucoma cannot be cured and the damage caused is irreversible. Progression of the disease can be managed and further deterioration of sight can be prevented if the condition is caught early.
Symptoms to look out for include a reduction in contrast between objects and their background, night vision problems, and a loss of side vision. Glaucoma initially damages the peripheral (side) vision, eventually leading to tunnel vision. Central vision may not be affected until a later stage.
Who is at risk?
Glaucoma is one of the leading causes of preventable blindness. Anyone can develop glaucoma but some are more at risk than others.
- Are you over 40?
- Do you have a parent, child or sibling with glaucoma?
- Are you shortsighted (myopia)?
- Are you Afro-Caribbean or Asian?
- Do you have any other medical conditions, like diabetes?
- Have you had past eye injuries?
When to have an eye exam
If you have any of the risk factors outlined above:
- Aged 20-29: eye exam every 3-5 years
- Aged 30-39: every 2-4 years
- Aged 40-64: every 2 years
- Aged 65 or older: every 1-2 years
If you have no risk factors:
- Aged 20-29: at least one eye exam during this time
- Aged 30-39: at least two eye exams during this time
- Aged 40-64: every 2-4 years
- Age 65 or older: every 2 years
Testing for glaucoma
Glaucoma has no symptoms in the early stages but can be detected during a routine eye test for glasses. Make sure to get your eyes tested regularly, even if you do not need glasses.
There are three tests for glaucoma; ask for all three. Having all three tests is much more effective in detecting glaucoma than having just one or two.
- A special torch is used to look into the back of your eye, checking for any damage to the optic nerve.
- The level of intraocular pressure is checked by blowing a puff of air into the eye. An eye specialist may use an anaesthetic drop with a yellow dye to numb the front of the eye, before shining a blue light into the eye and using a small instrument to lightly touch the eye and measure pressure.
- Visual field test – your peripheral vision is assessed to ensure that no areas of vision are missing. While watching a central light on a screen, you will be asked to click a button or say when other lights are flashed around it.
Remember: regular eye tests can help to prevent unnecessary sight loss.
Types of glaucoma
- Primary Open Angle Glaucoma
This is the most common form of glaucoma. The pressure in the eye rises slowly, without pain to warn of a problem, while the optic nerve is being damaged.
- Normal Tension Glaucoma
In glaucoma, the eye pressure is not always high. Glaucoma can develop where eye pressure is within the normal range but the optic nerve becomes damaged. This is known as normal or low tension glaucoma. In fact, about 20% of all glaucoma patients have this form of the disease.
- Angle Closure Glaucoma
This is a relatively uncommon type of glaucoma, which causes pain, blurring of vision and a red eye. Sometimes people may notice halos around street lights. This condition tends to occur over 24-48 hours, due to a very rapid rise in the eye pressure. Early treatment can reverse the problem and prevent long-term visual damage.
Secondary glaucoma occurs when another eye condition causes an increase in eye pressure. Babies can also have a rare eye condition called developmental or congenital glaucoma, which is caused by a malformation in the eye.
Early detection is vital in the treatment of glaucoma. Any damage caused is irreversible but the condition can be managed if caught early and further damage can be prevented.
The main treatment for glaucoma is eye drops. It is essential that drops are taken exactly as advised by your doctor. The drops will normally have to be taken for the rest of your life and although you may not notice any improvement in your vision, the drops are playing a vital role in lowering your eye pressure to prevent further damage.
Contact your doctor or nurse if you are having any difficulty with your eye drops.
Laser surgery or a minor surgery called trabeculectomy may be recommended for some types of glaucoma, in order to improve the drainage of fluids. During check-ups, your eye pressure and visual field will be monitored to assess the effectiveness of treatment.
Your eye specialist will discuss the best treatment with you.
Frequently Asked Questions
Will I always have glaucoma?
Damage caused by glaucoma is irreversible. It is important to prevent further glaucoma damage and progression of visual loss. This can be achieved by taking your eye drops. Surgery may make the subsequent treatment unnecessary although regular check-ups would be necessary.
Early detection is of the greatest importance.
Is there a cure?
No, there is no cure, but in the majority of cases the glaucoma can be well managed with the use of eye drops. A small percentage of people with glaucoma might need laser or surgery.
Will I go blind?
If glaucoma is not treated, damage can progress, causing a loss of peripheral vision. Glaucoma may eventually lead to complete visual loss. It is important to have regular and comprehensive eye examinations to detect any early signs of glaucoma damage.
What can I do?
Get your eyes tested regularly by a local optician or as advised by your eye specialist. Find out if you have a history of glaucoma in the family. If you have been diagnosed with glaucoma, follow your eye specialist’s instructions and take your eye drops as prescribed.