Our Optometrists answer your questions and gives advice on common eye problems.
Q: In my eyetest what is the puff of air on the eye for?
A: This is one of the tests we use to measure the fluid pressure of the eye to help detect glaucoma
The International Glaucoma Association’s slogan this year to raise awareness of this usually painless condition is:
“There’s a wonder to see every day don’t let Glaucoma get in the way.”
As vision accounts for nearly 70% of our sensory intake it is vital for life.
What is glaucoma?
It is the second highest cause of blindness in the UK
Like a dripping tap into a balloon—the fluid in the eye is made behind the lens of the eye in the muscle we use to focus – it then flows out through the pupil (which is the black hole in the middle of the coloured curtain of our eye) and through drainage pores around the outside edge of the cornea (the clear window at the front of the eye).
The production of fluid is continuous like the dripping tap and if there is too much fluid made, or the drainage route is too narrow then the pressure rises—this in turn pushes on the blood supply to the delicate nerves at the back of the eye that pass the visual signals to the brain. Once the nerve is damaged, it results in vision loss which cannot be restored – this is Glaucoma.
However, drops (and /or surgery ) are used to reduce the pressure in the eye and prevent further vision loss.
There are a number of tests that your optometrist will do to check for glaucoma:
1. The Intraocular Pressure. The pressure of the eye can be measured by a number of different instruments. The one you will probably remember is the one that makes you jump out of the chair by blowing air in your eyes– this acts like squeezing a bike tyre.
If this test makes your eyelids squeeze too much (or get in the way with blinks) we sometimes have to use drops to numb the eye and use a different device much like a spring balance .
2. Field of vision test. This is the very frustrating test that shows lots of different lights at different brightness levels within a bowl. The idea is to press a button indicating that you have seen the lights. The test therefore shows us how wide the side vision is and if there are any gaps. Glaucoma affects the outside areas first and so the patient is unaware of any vision loss until it comes closer into the middle.
The vision can have a patchy appearance but as Humans are very good at adapting to their environments they do not realise until it may be too late.
3. Fundoscopy. By Looking into eye we can see the optic nerve using various instruments and a photo or scan is useful to track any changes to its appearance.
Who is at risk?
Anyone can develop glaucoma. The risk of developing glaucoma goes up if you are:
- Aged over 40
- Very short-sighted
- Of African or Caribbean origin
- Closely related to someone with glaucoma.
Glaucoma tends to run in families. If one of your parents or children, or a brother or sister, has glaucoma, and you are over 40, the NHS will pay for your eye examination.
Because glaucoma causes no symptoms at first, if you are risk you must have regular eye examinations to detect it early.
For more information ask our staff or optometrists for a booklet or contact the IGA or RNIB for a booklet.
If you have any questions that you would like to ask please request an appointment .
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