Astigmatism is when the eye does not focus light evenly on the retina. This results in distorted or blurred vision at any distance. Other symptoms can include eyestrain, headaches, and trouble driving at night. If it occurs in early life, it can later result in amblyopia (a reduction in vision).
The cause of astigmatism is unclear, however it is believed to be partly related to genetic factors. The underlying mechanism involves an irregular curvature of the cornea or abnormalities in the lens of the eye. Diagnosis is determined with an eye examination.
Three treatment options are available: glasses, contact lenses, and surgery. Contact lenses can provide a wider field of vision while refractive surgery permanently changes the shape of the eye.
In Europe and Asia, astigmatism affects between 30 and 60% of adults. People of all ages can be affected by astigmatism. Astigmatism was first reported by Thomas Young in 1801.