Manual
Pupils & RAPD
The Eye Exam
Pupils & RAPD
Size, shape, reactivity and the swinging-flashlight test.
- 1Dim the room; patient fixates at distance (prevents near miosis).
- 2Measure size in dark and light; note shape.
- 3Direct and consensual response in each eye.
- 4Swinging-flashlight: 2–3 s on each eye, swing briskly. Paradoxical dilation of the illuminated pupil = RAPD on that side.
- 5Near response if light response is poor (light-near dissociation).
| Anisocoria worse in | Abnormal pupil | Think |
|---|---|---|
| Dark | Smaller pupil | Horner syndrome, physiologic |
| Light | Larger pupil | CN III palsy, Adie tonic pupil, pharmacologic, iris trauma |
An RAPD indicates asymmetric optic nerve or extensive retinal disease. Dense cataract or vitreous hemorrhage do not cause an RAPD.
Pupil-involving CN III palsy (dilated pupil + ptosis + down-and-out eye) = posterior communicating artery aneurysm until proven otherwise → emergent CTA/MRA.
Educational summary — follow local protocols and current guidelines.