What vision disorder causes blurred vision both near and far?

Astigmatism is a vision disorder that leads to blurred vision at both near and far distances. It is caused by an irregular shape of the cornea or lens, which prevents light from focusing properly on the retina. This irregularity can cause distortion or blurriness because the light rays do not converge at a single point, leading to difficulties in seeing clearly regardless of how close or far the objects are.

While myopia (nearsightedness) causes clear vision up close but blurry vision at a distance, and hyperopia (farsightedness) results in clear distance vision but blurry close vision, these conditions do not contribute to blur at both ranges. Presbyopia, which commonly occurs with aging, primarily affects the ability to see nearby objects clearly. Thus, astigmatism is unique among the listed options in its capacity to cause blurred vision at all distances.