Which of the following is a sign of ocular irritation?

The correct answer identifies a common symptom associated with ocular irritation. Itchy eyes are often a response to irritants, allergens, or infections. When the eyes are irritated, the body can produce itchiness as a reflexive response, prompting the individual to rub or touch their eyes, which may further exacerbate the irritation.

Redness of the sclera, swelling of the eyelids, and watery eyes can also be associated with ocular irritation and other conditions, but they emphasize different aspects of the irritation process or may relate to other underlying issues. Each of these signs can co-occur with itchiness but do not specifically highlight the sensation that is often a hallmark of irritative conditions, such as allergic reactions or exposure to environmental irritants. Thus, nothing encapsulates the immediate feeling of irritation better than itchy eyes.