Which of the drugs can cause a reduced blink rate?

The correct response indicates that multiple categories of medications have the potential to reduce the blink rate, which is critical for maintaining ocular health and comfort, especially for contact lens wearers.

Muscle relaxers can lead to a decreased blink frequency because they affect the nervous system, often leading to relaxed muscle tone and reduced motor function, including the muscles responsible for blinking. A lowered blink rate can subsequently contribute to dry eye symptoms, as blinking is vital for spreading tears evenly across the surface of the eye.

Antihistamines, commonly used to treat allergies, can cause dryness in the eyes and mouth by reducing secretions. This class of drugs can also influence the nervous system, resulting in a diminished urge to blink, which exacerbates dryness and irritation.

Antidepressants, particularly those with anticholinergic properties, can also reduce tear production and alter normal physiological responses, including the blink reflex. Since the blinking action helps to replenish tears and protect the cornea, any disruption can lead to discomfort and potential complications for contact lens users.

Hence, the fact that all these drug categories can contribute to a reduced blink rate supports the choice of the correct answer, as they all have mechanisms that interfere with normal blinking and tear stability.