Short-sightedness

Short-sightedness (myopia) is a very common eye condition and affects approximately 15 per cent of the population. If you are short-sighted, you will have trouble seeing objects clearly in the distance and they will appear blurry. You may not realise that you are short-sighted, because your vision may be changing slowly or you may think objects in the distance are blurry for everyone. Talk to your doctor, optometrist or ophthalmologist if you think you have vision problems.

Symptoms of short-sightedness

You may be short-sighted if:

• you have difficulty seeing objects in the distance
• objects in the distance appear blurry
• you need to squint or partially close your eyes to see clearly
• you get headaches that are caused by eyestrain
• you have difficulty seeing while driving and have trouble reading road signs, especially at night.

Short-sightedness in children

Typically, short-sightedness is first detected in childhood, during the early school years and may get worse until a person is approximately 20 years old. Some signs that your child may be short-sighted include:

• screwing up their eyes or squinting to see objects in the distance
• difficulty seeing the blackboard at school
• sitting close to the television or needing to sit at the front of the classroom.

Causes of short-sightedness

In people with short-sightedness, the clear front surface of the eye (the cornea) curves too steeply or the eyeball is too long. This means that light entering the eye does not focus on the back of the eye (retina), but focuses in front of the retina so the image appears blurry.

The causes of short-sightedness are unknown, although recent research suggests that it may be genetic. Short-sightedness tends to run in families. Your chance of developing short-sightedness is greater if you have family members with this type of eye condition.

Short-sightedness may also be related to environmental factors. Children who spend a lot of time focusing on near objects, for example, reading or watching a computer screen, may have a greater chance of becoming short-sighted. Also, lack of time outdoors in natural light may increase the chances of developing short-sightedness.

Diagnosis of short-sightedness

Short-sightedness is simple to diagnose. An optometrist or ophthalmologist usually asks you to read a special chart (Snellen chart) that has large letters at the top and smaller letters at the bottom. If you can see all the letters clearly you have 6/6 vision. If you have 6/12 vision, it means that you can read letters at 6 m that a person with normal vision can read from a distance of 12 m.

In everyday language, people still talk about 20/20 vision, which is a throwback to when Australia, like the USA, used imperial measurements and so 20/20 is the same as 6/6 vision.

Your eye healthcare professional will also check other aspects of your eye health and vision when you go for an eye test.

Treatment for short-sightedness

A cure for short-sightedness has not been discovered, although there are ways to improve your vision if you have this eye condition.

Ways to correct your vision if you are short-sighted include:

• wearing glasses – a simple and safe way to correct your vision
• wearing contact lenses – these are worn directly on the eye
• having laser surgery – a laser beam is used to change the shape of your cornea
• having intraocular lens surgery – your lens is replaced with a small plastic lens (intraocular lens).

If you are very short-sighted, you may be at an increased risk of other eye problems such as:

• stretching and thinning of the back of the eye (retina)
• holes and tears of the retina
• retinal detachment – the retina separates from the layer of blood vessels and without treatment you may become blind.
• Talk to your optometrist or ophthalmologist for more information.

Where to get help

• Your doctor
• NURSE-ON-CALL Tel. 1300 60 60 24 – for expert health information and advice (24 hours, 7 days)
• Your optometrist
• Your ophthalmologist