World Glaucoma Week 2021

an insightful look on blue colored eyes

What is glaucoma?

Glaucoma is the name for a group of conditions that damage the optic nerve. The optic nerve carries messages from the eye to the brain and so damage to it can lead to a loss of vision.

Your eye requires a certain amount of pressure to keep the eye healthy and in the correct shape. This pressure is controlled by the amount of fluid within the eye. If there is a build-up of fluid in the front part of the eye this can lead to an abnormally high eye pressure. This abnormal high pressure causes damage to the optic nerve. Glaucoma is not always caused by high pressure and sometimes pressure can be apparently normal, but damage can still occur because the optic nerve is weaker and more susceptible to damage from pressure.

Glaucoma can be subdivided in to 2 major types

  • Acute: Occurs suddenly and quickly
  • Chronic: A gradual, slow progressing condition

The chronic type of glaucoma is more common than the acute type and the most common form of glaucoma is known as Primary Open Angle Glaucoma (POAG).

It is estimated that in the UK about 2% of people older than 40 have chronic open angle glaucoma, and for people older than 75 this rises to 10%, this equates to around half a million people in the UK. Around 60 million people worldwide are currently living with glaucoma, which makes it the second most common cause of blindness in the world. This number is expected to rise further with changes in population demographics.

As chronic glaucoma tends to develop slowly over many years and because it normally affects the peripheral vision first, it often doesn’t cause noticeable symptoms until damage has already occurred.

The less common acute glaucoma does cause symptoms such as a sudden onset of severe eye pain and blurred vision and it is important to act quickly, if you get these symptoms even if the symptoms appear to go away.

Glaucoma damage can be prevented if detected and treated early. However, damage to the optic nerve can’t be reversed and so sight loss is irreversible. If untreated, it can cause blindness. Glaucoma usually affects both eyes, although it may be worse in one eye.


Paul Hopkins Optometrist and Professional Services Manager

Glaucoma is one of many conditions that can be detected at a routine eye test.

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How is glaucoma diagnosed?

During a routine eye tests the Optometrist will perform a range of tests to check for glaucoma including:

  • An eye pressure test, this is usually measure using a machine which blows a gentle puff of air at your eye, or by using drops to numb your eye and then gently pressing an instrument called a tonometer against it. Neither test hurts, although the puff of air may make you jump.
  • An examination of the retina including assessment of the optic nerve head. Using a bright light and / or capturing an image the optic nerve head can be viewed
  • A visual field tests may also be carried out to see check for any loss of peripheral vision, you will sit in a machine and be asked to look straight ahead and detect any spots of light that flash into your vision.

If glaucoma is suspected, the optometrist will make a referred to a specialist doctor, known as an Ophthalmologist, who will be able to confirm the diagnosis and assess any damage that has occurred.

How is glaucoma treated?

Glaucoma is treated to prevent further damage to the optic nerve.
The main treatment options currently available are:

  • Eye drops to either reduce the amount of fluid being produced in the eye or to improving and increase drainage of the fluid.
  • Laser treatment to improve fluid drainage
  • An Operation is only required in a small number of cases. A surgeon improves fluid drainage by creating a new drainage channel within the eye.

What does it mean if your patient has high pressure inside their eye, but doesn’t have glaucoma?

This is condition is known as ocular hypertension. Some people naturally have eye pressure above ‘normal’ range, but as this pressure doesn’t cause any damage to their optic nerve this is not glaucoma and as no damage is caused, treatment is not required. Although you may not be seen by the eye clinic it is important to visit your optometrist for regular eye test to ensure any future changes are detected.

Glaucoma is one of many conditions that can be detected at a routine eye test and it is recommended that you have an eye test at least every two years.


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References

  • 1 https://www.nice.org.uk/guidance/ng81/resources/glaucoma-diagnosis-and-management-pdf-1837689655237