Which type of optical defect causes difficulty in seeing fine details?

Astigmatism is an optical defect characterized by an irregular curvature of the cornea or lens, which causes light rays to be focused at multiple points rather than a single point on the retina. This leads to blurred or distorted vision, particularly when trying to see fine details. Individuals with astigmatism often struggle to achieve sharp vision, as the varying focal points result in a lack of clarity. Consequently, this condition directly impacts the ability to discern intricate details, making it essential for affected individuals to seek optical correction, such as glasses or contact lenses, to alleviate the difficulty in seeing fine details.

Other conditions like ametropia, anisometropia, and aphakia also affect vision, but they manifest different challenges. Ametropia refers to any refractive error, including nearsightedness and farsightedness, while anisometropia refers to a significant difference in refractive power between the two eyes. Aphakia, which is the absence of the eye's lens, primarily affects focusing ability but does not specifically relate to the difficulty in seeing fine details in the same direct way as astigmatism does.