Short-sightedness is a common eye condition that causes distant objects to appear blurred, while close objects can be seen clearly.

It's thought to affect up to one in three people in the UK and is becoming more common.

The medical term for short-sightedness is myopia.

Cases of short-sightedness can range from mild, where treatment may not be required, to severe, where a person's vision is significantly affected.

The symptoms of short-sightedness often start around puberty and gradually get worse until the eye is fully grown.

If distant objects appear fuzzy to you or if your child is finding it difficult to see things in the distance, such as the blackboard at school, you should make an appointment for a sight test with an optometrist (optician).

Find your nearest optician.

What causes short-sightedness?

Short-sightedness is a refractive eye condition. Refractive eye conditions occur when problems with the eye's structure affect how light enters the eye.

Most people are born slightly long-sighted (hyperopia), where close objects appear blurred. This is because at birth the eyes have not grown to their full length.

Children are able to "accommodate", which means they can overcome the long-sightedness. After the eyes have grown to their full length (by around eight years of age), the sight is normal. This is known as emmetropia.

However, in short-sightedness, the eyes keep growing and become too long from front to back. This means that light doesn't reach the light-sensitive tissue (retina) at the back of the eye. Instead, the light rays focus in front of the retina, resulting in distant objects appearing blurred. Unlike long-sightedness, it isn't possible to overcome short-sightedness.

Short-sightedness is usually caused by a combination of genetic and environmental factors that disrupt the eye's normal growth.

Read more about the causes of short-sightedness.

Diagnosing short-sightedness

Short-sightedness is usually diagnosed by an optician during an eye test.

A simple test will be used to help assess your vision. You may be asked to read from a chart that has rows of letters that get smaller on each line.

If you have problems reading the letters at a distance that most people can read easily, it is likely that you are short-sighted.

Read more about how short-sightedness is diagnosed.

Treating short-sightedness

Short-sightedness can be treated in three ways:

• using corrective lenses such as glasses or contact lenses to compensate for the structural defects in the eye
• using laser surgery to correct the defect (children cannot have laser surgery because their eyes are still developing) – most people have to pay for private laser surgery
• implanting an artificial lens into the eye to compensate for the longer eye length in people who are severely short-sighted

Read more about treating short-sightedness.

Associated eye conditions

If you have severe short-sightedness (high degree myopia), you are more likely to develop other eye disorders in later life. These might include:

• retinal detachment – where the retina pulls away from the blood vessels that supply it with oxygen and nutrients
• glaucoma – where high eye pressure damages the optic nerve at the back of the eye 
• cataracts – where cloudy patches develop inside the lens of the eye
• macular degeneration – where the central section of the retina (the macular) becomes damaged, leading to some loss of central vision

Read more about other eye conditions associated with short-sightedness.