Which condition is characterized by an inability of the eye to focus sharply?

The condition characterized by an inability of the eye to focus sharply is astigmatism. This refractive error occurs when the cornea, the clear front surface of the eye, is not perfectly spherical, causing light rays to be focused at multiple points either in front of or behind the retina. As a result, this leads to blurred or distorted vision at various distances.

Astigmatism often presents itself alongside other refractive errors such as myopia or hyperopia but is specifically linked to the irregular shape of the cornea or lens, making it difficult for the eye to focus clearly on objects. People with astigmatism may find that they experience vision problems, particularly when trying to see fine details or during tasks that require sharp focus.

In contrast, conditions like myopia primarily involve difficulty seeing distant objects clearly due to the eye being too long or the cornea being too curved, affecting how light is focused inside the eye. Retinoblastoma is a type of eye cancer that typically affects young children and does not specifically relate to focusing issues, while retinitis pigmentosa is a degenerative eye disease that affects the retina and leads to loss of vision over time. Thus, astigmatism stands out as the condition directly relevant to