What is Astigmatism?

Astigmatism is a common condition which occurs when the cornea (the clear front surface of your eye) or the lens inside your eye are irregularly shaped.

Normally the cornea and the lens are smooth and curve equally in all directions, like a soccer ball. This enables light rays to focus directly onto your retina (the camera film at the back of your eye).

When the cornea or lens are not smooth or regularly shaped, like an AFL football, light rays aren’t refracted (bent) properly onto the retina, causing blurry vision at any distance.

If the cornea alone is irregularly shaped, you have corneal astigmatism, and if the lens is distorted, you have lenticular astigmatism.

Astigmatism often occurs with other vision conditions such as myopia (nearsightedness) and hyperopia (farsightedness). Together these conditions are called refractive errors because they affect how your eyes bend or refract light.


What causes astigmatism?

It’s not yet known why corneal shape varies from person to person, but the likelihood of developing astigmatism is inherited and it’s usually present from birth.

Non-congenital astigmatism can occur in other ways, including:

  • When the curvature of the lens inside your eye alters, bringing either an increase or decrease in astigmatism. This change occurs frequently in adulthood and may precede the development of cataracts.
  • After an eye injury or eye surgery
  • Through uncommon eye conditions such as keratoconus where the cornea becomes progressively thinner and cone-shaped, or pellucid marginal degeneration.

What are the symptoms of astigmatism?

  • Blurry vision
  • Distorted vision
  • Eyestrain
  • Squinting to try to see clearly
  • Headaches
  • Eye discomfort

How is astigmatism diagnosed?

  • Astigmatism is diagnosed through a comprehensive eye examination where your eye doctor will:
  • Measure your refraction
  • Measure the curvature and generate a contour map of your cornea using a corneal topographer
  • Examine your eyes with a slit lamp

How is astigmatism treated?

Treatment aims to improve vision clarity. There are several options available for treating your astigmatism which include:

  • Glasses
  • Contact lenses
  • Laser and other refractive surgery procedures which improve vision and reduce the need for glasses or contact lenses

Your ophthalmologist will discuss your most appropriate options with you.

Download the fact sheet

Need to know more?

All of our ophthalmologists here at the Lions Eye Institute can help you with advice on astigmatism at your consultation. You’ll need a current referral from either a GP or an optometrist to schedule an appointment.

You can request an appointment below.

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