What visual problem is caused by light rays coming to a point of focus unevenly?

Astigmatism occurs when the eye's cornea or lens has an irregular shape, causing light rays to bend unevenly as they enter the eye. This uneven bending prevents light from coming to a single point of focus on the retina, leading to blurred or distorted vision. In contrast to conditions such as myopia (nearsightedness) or hyperopia (farsightedness), which involve light focusing too soon or too late, respectively, astigmatism specifically relates to the way light is focused unevenly due to the shape of the eye's refractive surfaces. This unique characteristic of astigmatism means that it can affect distance and near vision, leading to difficulties in seeing clearly at various distances. Understanding this distinction is crucial for recognizing how different refractive errors impact vision.