Astigmatism is a very common focussing error of the eyes which causes blur. It is caused by the shape of the eye, usually due to the cornea’s surface or occasionally due to the eye’s lens being tilted. Sometimes astigmatism can be inherited but it often happens as a normal characteristic of growth.

Blur from astigmatism is not like that from myopia where all of an image is equally blurred, because some parts of the image are more out of focus than others. If you look at the line diagrams, you can see the effect of astigmatism by tilting the tip the page down and facing away from you the lines running across the page are less distinct than those running away from you.
The blur of astigmatism makes things uncomfortable to look at, difficult to focus and may cause headaches, tiredness and poor concentration.
What about tired eyes?
Astigmatism can also result in fatigued eyes, especially if you are concentrating on anything for a long period of time, whether looking up close (for example, studying or computer use) or in the distance (for example, driving).

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