Like longsightedness and shortsightedness, astigmatism is another optical imperfection of the eye.
If you have perfect sight, then as light enters the eye, it is carefully focussed by various components of the eye to form a point on the retina.
Eyes without astigmatism have a round shape, resulting in a constant focusing effect over the cornea. In astigmatism, the front of the eye has an oval shape resulting in a variable focusing effect over the cornea.
As a result, there are 2 main focal points.
Astigmatism can occur with shortsightedness, longsightedness or on its own.
The greater the astigmatism, the greater the blur. Generally, astigmatism causes blur at all distances. Correction involves refocusing light back onto the retina.
There are several options, however, the most common ones are spectacles, contact lenses and refractive surgery.