What is the effect of atropine on the pupil?

Atropine is an anticholinergic agent that exerts its effects on the eye primarily by blocking the action of acetylcholine on the muscarinic receptors of the iris sphincter muscle. This blockade leads to relaxation of the sphincter muscle, resulting in pupil dilation, a condition known as mydriasis. The dilation of the pupil occurs because atropine inhibits the parasympathetic control that normally constricts the pupil in response to light or near vision.

Furthermore, atropine is often used in clinical settings for various purposes, including as a part of an eye examination to allow for a better view of the retina and for treatment of certain eye conditions. It is important for those studying ophthalmology to understand the pharmacological effects of medications like atropine, as this knowledge is crucial for application in patient care and understanding the physiological responses of the eyes.