Final answer:
Dilating eye drops are called mydriatics, which include substances like phenylephrine that cause dilation of the pupil by binding to adrenergic receptors in the iris during an eye exam.
Step-by-step explanation:
Dilating eye drops are referred to as mydriatics. These drops cause mydriasis, which is the dilation of the pupil, and this effect occurs when substances such as phenylephrine bind to adrenergic receptors in the radial fibers of the iris' smooth muscle. This is a sympathetic system response, and these drops are typically used during an eye exam in an ophthalmologist's or optometrist's office. On the other hand, pilocarpine is a muscarinic agonist used to reverse mydriasis after procedures.