Certified Ophthalmic Medical Technologist (COMT) Practice Exam

Which mydriatic agent should be avoided in pregnancy due to its vasoconstrictive effects?

1. Atropine

2. Phenylephrine hydrochloride

3. Tropicamide

4. Brimonidine

The correct answer is: Phenylephrine hydrochloride

The choice of phenylephrine hydrochloride as the mydriatic agent to avoid during pregnancy is correct due to its potent vasoconstrictive effects. Phenylephrine is a selective alpha-1 adrenergic agonist that induces mydriasis by constricting the pupil's dilator muscle while also influencing systemic vascular resistance, which can lead to increased blood pressure. During pregnancy, maintaining proper blood flow and avoiding excessive vasoconstriction is crucial for maternal and fetal health. The use of agents that can cause significant vasoconstriction raises concerns about potential impacts on uteroplacental circulation, thus increasing the risk of complications. Other mydriatic agents listed may have their own side effects and considerations but are generally deemed safer for use in pregnant patients compared to phenylephrine. For example, tropicamide is typically chosen for its rapid onset and short duration, while atropine is used less frequently for mydriasis in this population due to its systemic anticholinergic effects. Brimonidine, typically used for lowering intraocular pressure, has a different mechanism and is primarily not selected for inducing mydriasis.