The eyeball is naturally round but when it is slightly less rounded, the vision may be blurred depending upon the extent of difference in shape which is then termed as astigmatism.

Mild astigmatism is usually well tolerated and may not require correction with glasses or contact lenses. A higher degree of astigmatism, mostly in combination with other refractive errors such as long or short sightedness, usually requires correction. However, for those requiring a more permanent correction or where glasses are a hindrance to activities such as sport, toric lens implants can offer a more permanent solution which requires surgery and replacement of the natural lens.