If the curvature of the front of the eye is uneven, light will refract unequally and may result in blurred vision.
Many people are unhindered by a little astigmatism although having more than 1 dioptre especially if it is combined with other refractive conditions such as myopia ( short sightedness) or long sightedness
( hyperopia) may require correction.
Astigmatism can be corrected by glasses and sometimes by contact lenses. It can also be corrected with laser surgery or by surgical techniques during cataract or lens replacement surgery.