What does the term 'astigmatism' refer to?

Astigmatism refers specifically to an irregular curvature of the cornea or lens, leading to distorted or blurred vision. In a normal eye, light rays are directed towards a single focal point on the retina. However, in the presence of astigmatism, the uneven curvature causes light rays to focus on multiple points, preventing clear vision. This distortion can affect vision at all distances.

The other options describe different eye-related conditions: one pertains to color perception issues, another involves dryness of the eyes, and the last addresses infections. These conditions are distinct from astigmatism and involve different aspects of vision and ocular health. Understanding astigmatism as a refractive error is crucial for seeking appropriate corrective measures, such as glasses or contact lenses specifically designed to compensate for the irregular shape of the cornea.