Short-sightedness, or myopia, is a very common eye condition that causes distant objects to appear blurred, while close objects can be seen clearly.
It's thought to affect up to 1 in 3 people in the UK and is becoming more common.
Short-sightedness can range from mild, where treatment may not be required, to severe, where a person's vision is significantly affected.
In children the condition can start from 6 to 13 years. During the teenage years when the body grows rapidly myopia may become worse. Myopia can occur in adults.
Signs that your child may be short-sighted can include:
If you think you or your child may be short-sighted, you should book an eye test at a local opticians.
You should have a routine eye test at least every 2 years, but you can have a test at any point if you have any concerns about your vision.
An eye test can confirm whether you're short or long-sighted, and you can be given a prescription for glasses or contact lenses to correct your vision.
For some people, such as children under 16 or those under 19 and in full-time education, eye tests are available free of charge on the NHS.
Read about NHS eyecare entitlements to check if you qualify.
Read more about diagnosing short-sightedness.
Short-sightedness usually occurs when the eyes grow slightly too long.
This means that light doesn't focus on the light-sensitive tissue (retina) at the back of the eye properly.
Instead, the light rays focus just in front of the retina, resulting in distant objects appearing blurred.
It's not clear exactly why this happens, but it often runs in families and has been linked to focusing on nearby objects, such as books and computers, for long periods during childhood.
Ensuring your child regularly spends time playing outside may help to reduce their risk of becoming short-sighted.
Read more about the causes of short-sightedness.
Short-sightedness can usually be corrected effectively with a number of treatments.
The main treatments are:
Read more about treating short-sightedness.
Some adults with severe short-sightedness and young children with untreated short-sightedness are more likely to develop other eye problems.
These can include: