Astigmatism

Astigmatism is a condition in which the refractive power of the eye is not the same in all meridians, resulting in what we see before us not being uniformly focused.

This usually happens because the cornea does not have the same curvature in all axes.

Astigmatism can coexist with myopia or hyperopia. It is distinguished in many types and can be smooth or bumpy (depending on whether the meridians
with the maximum difference in curvature are perpendicular to each other or not), "according to the rule" (if the vertical axis is more curved) or "despite the rule '(if the horizontal axis is more curved), myopic or hyperopic, and simple, complex or mixed (depending on whether the focal lines are front, rear, or one in front and the other behind the retina).

The blurred vision astigmatism brings is present at all distances and the fatigue it causes is significantly larger than the other refractive
disabillities, due to the continuous effort of the ciliary to focus on an object, but of course it is never possible to achieve.

Astigmatism does not show significant changes during lifetime. Significant changes in astigmatism may indicate other serious problems and needs further investigation.

Usually astigmatism is not important and does not create functional problems. A child though that sees for example 3/10 because of astigmatism is worse off than a child who sees 3/10 due to simple myopia, because it cannot improve low resolution by just approaching (decreasing distance) an object.

Astigmatism is not only characterized by its degree (in diopters) but from its angle too (in degrees), which must be properly measured and prescribed accurately, especially in cases of large astigmatism.