Astigmatism is characterized by an irregular curvature of the cornea. This is one type of refractive error. Astigmatism occurs in nearly everybody to some degree. As for the causes, it parted as two types. Generally, it has same symptoms such as:
- Blurred or distorted vision at all distances.
- Photophobia – sensitivity to light.
- Excessive squinting.
- The person is constantly closing his/her eyes.
- Eye strain – occurs more often when the eye has to focus for long periods, as in reading from paper or a computer monitor.