What is astigmatism?

Astigmatism is accurately described as an eye condition stemming from the irregular shape of the cornea or lens. In a healthy eye, the cornea and lens are evenly curved, which allows light to focus directly on the retina. However, with astigmatism, these structures are not uniformly curved, leading to multiple focal points. This results in distorted or blurred vision at various distances.

Understanding the other choices can help contextualize why they do not define astigmatism. The inability to see close objects refers more specifically to presbyopia or hyperopia, while loss of vision in one eye is typically associated with conditions such as amblyopia or strabismus. Excessive tearing is not related to the structural issues that characterize astigmatism but can instead be symptomatic of other eye ailments like dry eye syndrome or allergies. Thus, the correct designation of astigmatism focuses on the uneven curvatures that disrupt normal vision.