Understanding Astigmatism

Nicole Herbert - B.Optom (UJ), N.Dip Optical Dispensing (CPUT)

You may recognize this word from previous eye examinations, but very few actually understand what it means, so I will hopefully be able to demystify the word for you.

Astigmatism is the name given when either the cornea (front surface) or the lens of the eye has an irregular curvature. Both the surfaces of the cornea and lens of the eye are surfaces that bend the light entering the eye, sending it to the retina where it should form a clear image. If the light falls on a surface that is irregular, the light that reaches the retina is distorted, giving you blurry, hazy vision.

How did I get astigmatism?

Although sometimes difficult to determine, there are a few possible causes of astigmatism:

  • it is hereditary

  • as a result of a previous corneal operation or injury

  • thinning of the cornea (as with Keratoconus)

  • excessive rubbing of the eyes (as seen in those who have bad allergies)

  • in combination with near-sightedness or farsightedness

Do I have astigmatism?

While the only way to know if you have astigmatism is to have an eye examination performed by your eye care professional, there are a few tell-tale signs that you may have astigmatism:

  • blurry distorted vision

  • problematic night vision

  • eyestrain

  • headaches

  • squinting

I think I have astigmatism... what next?

During your routine eye examination, your eye care professional will be able to confirm the presence and quantity of astigmatism, if any. Usually, this would be corrected with either spectacles or contact lenses (depending on the nature and quantity present).

Should there be any other possible reason for the astigmatism – e.g. an eye condition such as Keratoconus (an excessive thinning of the cornea), then further treatment options will be discussed, as necessary.