Final answer:
Atropine eye drops are not used in eye examinations due to their extensive duration of action which can lead to prolonged pupil dilation, making the recovery of normal vision take several days.
Step-by-step explanation:
The primary reason that atropine eye drops are NOT used in eye examinations is because C. Atropine has extensive duration of action in the eyes. Atropine is a muscarinic antagonist that dilates the pupil by blocking acetylcholine receptors. This effect is useful for certain treatments but in the context of an eye examination, the prolonged effect of atropine is not desirable. It causes prolonged dilation (mydriasis) which can take several days to wear off, making it impractical for routine examinations where patients need to recover normal function quickly. In contrast, other agents like phenylephrine cause mydriasis but have a shorter duration of action which is preferable for eye exams.