1. a defect in the eye or in a lens caused by a deviation from spherical curvature, which results in distorted images, as light rays are prevented from meeting at a common focus
Usage: medical; optics

Examples

• The eye doctor diagnosed her with astigmatism and prescribed corrective lenses.
• His astigmatism made it difficult to see clearly at any distance without glasses.
• The optometrist explained that astigmatism is caused by an irregularly shaped cornea.
• Many people have mild astigmatism without even realizing it.
• Contact lenses designed for astigmatism are called toric lenses.
• The camera lens suffered from astigmatism, producing blurry photographs.