afferent pupillary defect
Pronunciation: AF-er-ent PYOO-pil-ar-ee DEE-fekt
A condition where one pupil responds less to direct light than consensual light, indicating optic nerve damage.
Full Definition
An afferent pupillary defect (APD) occurs when there is damage to the optic nerve or severe retinal disease, causing the affected pupil to respond poorly to direct light stimulation while maintaining normal consensual response. This finding is detected using the swinging flashlight test and is a critical diagnostic sign in neuro-ophthalmology. The Marcus Gunn pupil is the most common type of APD, named after the Scottish ophthalmologist who first described it.
Usage
Usage note: Often abbreviated as APD or RAPD in clinical notes; editors should ensure the full term is spelled out on first use.
In Context
- "The patient exhibited a clear afferent pupillary defect in the left eye, consistent with optic neuritis." — Clinical examination report
- "Documentation of the afferent pupillary defect should include the degree of the defect using neutral density filters." — Medical record guidelines