In some instances, glaucoma may be linked to increased pressure of the fluid inside the eye pressing on the nerve, while in others it is thought to be due to reduced blood flow.
In all cases however, the impact is a gradual impairment in the sensitivity of parts of the retina, increasingly causing areas of loss of vision and the ‘visual field’. Often, patients do not have any symptoms in the early stages of glaucoma, so regular eye screening is essential to detect this condition.
There are two main types of glaucoma; chronic (developing slowly) and acute (which involves a sudden onset). In the early stages of chronic glaucoma, there are few if no symptoms - as the condition progresses the extent of the peripheral vision reduces.
In acute glaucoma the following symptoms may be experienced:
- Short bursts of pain, discomfort and in extreme cases nausea.
- A brow ache that comes and goes.
- Seeing coloured rings around bright lights.
- Hazy or misty vision.
The eye needs a certain amount of pressure to keep its shape and to function correctly. The balance of pressure is maintained by the aqueous humour, the eye’s internal watery liquid.
In some cases of glaucoma, optic nerve damage is caused because there is more fluid being produced than draining away, leading to the build-up of pressure. Glaucoma can also be caused by a weakness in the optic nerve.
Certain groups of people are more at risk of glaucoma, especially those who are:
- Aged over 40.
- Very short sighted.
- Of African, Caribbean, East Asian or South Asian origin.
- Closely related to someone with chronic glaucoma.
- Already have raised tension within the eye.
During an eye test an Optometrist will carry out several tests that can detect any signs of glaucoma by:
- Measuring your eye pressure – usually using the “puff of air” test or sometimes with yellow drops and a blue light.
- Examining your optical nerve using an optical microscope, looking for signs of pressure build up.
- Assessing the peripheral extent of your field of vision.
If glaucoma is detected then your Optometrist will refer you to the hospital for further diagnosis and treatment, usually involving eye drops to reduce the pressure. Although damage caused by glaucoma can’t be cured, early diagnosis, constant monitoring and treatment can help minimise the rate of progression.
If you drive and have been diagnosed with glaucoma, you must inform the DVLA.
We recommend you have an eye test at least every two years regardless of symptoms and/or conditions. If you are over 40 and have a family history of glaucoma then we recommend you have an eye test every 12 months.
More information can be found on the glaucoma association website. You can also call the information, support and advice service, Sightline, on 01233 64 81 70.
If you're experiencing any of the symptoms mentioned, please make an appointment with the optical expert at your nearest Vision Express store.