Spotting signs: common eye conditions to know

Your eye is an amazingly complicated - and well designed - bit of kit
. Gradual eyesight changes are normal, but you need to know the signs that need medical care. With regular maintenance, there's a good chance your eyes will last a lifetime.

At the front of the eye is the pupil, which lets light through onto the back of your eye. Surrounding it your iris, made up of muscleswhich close your pupil to avoid letting too much through. Light falls on a lens which focuses the light on to the retina - a layer at the back of your eye. This contains millions of light-sensitive 'rods and cones' which pass messages to your brain about what you're seeing.

We sort of take it for granted that our eyesight will get gradually worse from middle age onwards. From about your mid forties, the lens at the front of your eye gets less able to change shape in order to focus on close objects. That means most people with previously normal eyesight will need glasses for reading - although interestingly, if you've always been short-sighted you may not need reading glasses. Regular eye checks and changing your glasses prescription will avoid eye strain.

Some eye symptoms are 'red flags' - medical emergencies that could threaten your eyesight if you don't get immediate help. They include:

  • A red eye with pain (rather than soreness), reduction in eyesight or sensitivity to light
  • A painful red eye if you've had recent eye surgery, previous glaucoma surgery or wear contact lenses
  • Sudden greying or blacking out of vision in one eye
  • Double vision which goes away if you close one eye
  • Flashing lights, or a large number of 'floaters' (dark shapes floating across your line of sight).

In cataracts, the lens at the front of your eye becomes cloudy. Colours may look faded or tinged with yellow/brown; you may get bright 'haloes' around bright lights, or find them dazzling; and you'll often find your vision misty or blurred. If it reaches the stage where your eyesight is having a significant impact on your life, cataracts can be easily treated by removing them under local anaesthetic and replacing them with a plastic lens.

Age-related macular degeneration, or ARMD, is the commonest cause of vision loss in over-50s. Cells in the macula - the part of the retina with most rods and cones, which provides central vision (for reading, writing, seeing fine detail) - wear out. It doesn't cause blindness - your 'peripheral vision' isn't affected. But central vision gets blurred, colours less bright and straight lines can look wavy. Most people get 'dry' ARMD, which isn't treatable but which comes on gradually and is usually less severe. About one in 10 get 'wet' ARMD, which quickly causes significant loss of vision but can be treated with injections into your eye.

But there are some important eye problems you won't know about without regular eye checks. One is glaucoma - a condition where the pressure inside the eyeball is raised. Glaucoma runs in families, and you're eligible for free eye tests over 40 if a close relative has it. You may not know you've got it, but it puts you at increased risks of a sudden huge spike in pressure inside the eye, which can cause blindness if it's not treated. An optician's check will pick this up and you can be referred for regular specialist check-ups and long-term eye drops to keep the pressure controlled.

If you have diabetes, it's crucial to get regular eye checks - the UK is one of the only countries in the world to offer annual specialist eye tests to everyone with diabetes, to check for damage called diabetic retinopathy. If picked up early, this can be treated to minimise loss of eyesight. But prevention is better than cure, and keeping your blood sugar, blood pressure and cholesterol well controlled can stop it happening in the first place.

With thanks to 'My Weekly' magazine where this article was originally published.

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. Patient Platform Limited has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.