Astigmatism may be present from birth, develop as you age, or may be due to injury or disease.

Eye check-ups can diagnose astigmatism and it can be treated with glasses, contact lenses or laser eye surgery.

What is astigmatism?

The shape of the outside surface of your eye (the cornea) and the lens inside your eye are important for focusing and clear vision.

Astigmatism occurs when the shape of the cornea or the lens of the eye is not a perfectly smooth curve.

The result is blurred vision — mildly blurred for some people, severely blurred for others.

Causes of astigmatism

Astigmatism may be present at birth or develop with ageing, and may have a hereditary component. It can also result from eye disease or injury.

Types of astigmatism

There are two types of astigmatism:

• regular — where the cornea is curved more in one direction (say vertically) than the other (say horizontally)
• irregular — where the curvature of the cornea is uneven across the surface of the eye

Symptoms of astigmatism

• blurred vision
• headaches
• tiredness
• difficulty seeing at night
• squinting
• eye strain, especially after concentrating for a long time
• a 'lazy eye' in children

Astigmatism involves poor focus at all distances. People who have astigmatism may also experience:

• long-sightedness (hyperopia)
• short-sightedness (myopia)

Diagnosis of astigmatism

Your optometrist or ophthalmologist (specialist eye doctor) can diagnose astigmatism with an eye examination.

Testing may include:

• vision testing
• measurement of the curve of your corneas
• measurement of how well your eyes focus light

If you have any concerns about your eyesight, see your optometrist or talk to your doctor.

Astigmatism in children

Because astigmatism can be present from birth, it is important to have your child’s eyesight checked if you are concerned about their vision.

Treatment of astigmatism

For most people, astigmatism is a mild condition and does not need any treatment beyond correction with glasses or contact lens. More severe astigmatism may need treatment.

Treatments for astigmatism include:

• corrective glasses or contact lenses
• orthokeratology, which uses rigid contact lenses to reshape the cornea
• laser eye surgery, which reshapes your cornea