As a result, the light will focus on two points on the retina instead of one, causing blurry vision and, sometimes, double vision. In a person with astigmatism, the cornea is often egg- or football-shaped and curves differently from top to bottom than it does from side to side, rather than being perfectly round. It transmits and focuses light onto the back of the eye. The cornea is a transparent layer of tissue that covers the front of the eye. Irregular astigmatism can often result from trauma, surgery, or keratoconus, which is the thinning of the cornea.Īstigmatism happens when there is an irregular curvature of the cornea, the lens, or both. In irregular astigmatism, the two curves are not at 90-degree angles to each other, and the curvature of each is not uniform or even. If astigmatism is regular, the two curves are at a 90-degree angle to each other, and the curvature of each is uniform. Mixed astigmatism: This is when one curve produces symptoms of hyperopia and the other produces symptoms of myopia.Īstigmatism can also be regular or irregular: Regular astigmatism.Hyperopic astigmatism: This occurs when hyperopia combines with astigmatism, and the two curves are focused behind the retina.Myopic astigmatism: Myopic astigmatism happens when astigmatism combines with myopia, and the two curves in the cornea or the lens - the curves from top to bottom and side to side - are focused in front of the retina.Irregular astigmatism: In this type, the curvature of the cornea is uneven.Īstigmatism can also occur with myopia, hyperopia, or both:.Lenticular astigmatism: This type of astigmatism occurs due to changes in the eye’s lens.Corneal astigmatism: This is the most common type of astigmatism.eyestrain, especially when the eye has to focus for long periodsĪ person with these symptoms may not have astigmatism, but it is advisable to have an eye exam to check.blurred or distorted vision at all distances.The following are common signs and symptoms of astigmatism: Share on Pinterest ER Productions Limited/Getty Images

Irregular pupil shape