If there is astigmatism in the eye, it causes blurred vision due either to:

  • The irregular shape of the cornea – the clear front cover of the eye, or
  • How the lens is curved inside the eye.

Irregular shaped cornea

If the cornea of your eye is irregularly shaped or prevents light from focusing properly on the retina (the light sensitive surface at the back of your eye) your vision may become blurred at any distance.

Astigmatism is very common. Most people have some astigmatism. Slight amounts of astigmatism usually won’t affect your vision and you won’t need treatment. However, larger amounts cause distorted or blurred vision, eye discomfort and headaches.

Astigmatism frequently occurs with other vision conditions like short-sightedness (myopia) and long-sightedness (hyperopia).

The specific cause of astigmatism is unknown. It can be hereditary and people are usually born with it. It can change as a child grows and may decrease or worsen over time.

Refractive errors

Astigmatism is called a ‘refractive error’ because it affects how the eyes bend or ‘refract’ light.

Glasses or contact lenses

A comprehensive optometric examination will include testing for astigmatism. Depending on the amount of astigmatism present, your optometrist can provide eyeglasses or contact lenses that correct it by changing how light enters your eyes.

Cornea modification

Sometimes, astigmatism can be treated my treating the cornea with a procedure called OrthoKeratology (Ortho-k). It is a painless, non-invasive procedure that involves wearing a series of specially designed rigid contact lenses to gradually reshape the curvature of the cornea.

Laser surgery

Laser surgery is also a possible treatment for some types of astigmatism. It changes the shape of the cornea by removing a small amount of eye tissue. This is done using a highly focused laser beam on the surface of the eye.