Which of the following is a sign of a common refractive error?

Blurred distance vision is a prominent sign of a common refractive error, particularly myopia (nearsightedness). In individuals with this condition, the eye focuses images in front of the retina rather than directly on it, leading to difficulty seeing distant objects clearly while nearer objects may still be visible. This symptom typically prompts individuals to seek an eye examination and can indicate the need for corrective lenses to improve their visual clarity at a distance.

On the other hand, increased contrast sensitivity, sharp near vision, and enhanced color perception are not typically associated with refractive errors. Increased contrast sensitivity refers to the ability to distinguish between different shades and is more related to the health of the eye rather than its refractive state. Sharp near vision can occur in individuals with myopia, but it is not a sign of refractive error; rather, it often indicates that their near vision is functioning adequately when distance vision is impaired. Enhanced color perception is not directly linked to refractive errors but can vary based on the individual's visual system, and thus does not serve as an indicator of these common errors.