[Sleep modifies anticholinergic mydriasis]

Area of Science:

• Ophthalmology
• Neuroscience
• Pharmacology

Context:

• Pupil size reflects alertness and sleep depth.
• Miosis (pupil narrowing) occurs during sleep, sedation, and anesthesia due to decreased sympathetic tone.
• Anticholinergic mydriatics (tropicamide, cyclopentolate, atropine) may be less effective in dilating pupils when sympathetic tone is low.

Purpose:

• To investigate the effect of sleep and reduced sympathetic tone on pupil dilation in children treated with mydriatic eye drops.
• To determine if parasympatholytic mydriasis is dependent on sympathetic tone.
• To establish the necessity of sympathomimetic agents for maintaining mydriasis in sedated or sleeping patients.

Summary:

• Children receiving mydriatic eye drops for diagnostic pupil dilation showed unsatisfactory dilation during sleep.
• This reduced response to anticholinergic mydriatics was overcome by administering phenylephrine, a sympathomimetic agent.
• The study demonstrates that parasympatholytic mydriasis is influenced by sympathetic tone, and sympathomimetics are crucial for maintaining pupil dilation in deep sleep, sedation, or anesthesia.

Impact:

• Highlights the importance of considering sympathetic tone when assessing pupil dilation.
• Suggests that phenylephrine administration is mandatory for maintaining mydriasis in conditions of reduced sympathetic tone, such as sleep or anesthesia.
• Provides crucial information for ophthalmologists and anesthesiologists regarding pupil management in specific patient populations.