Pupilla learning lab
RAPD & Swinging Flashlight Test Simulator
Practise the swinging flashlight test and observe a relative afferent pupillary defect on a virtual patient. Compare right- and left-eye responses with the normal examination.
- Free in your browser
- English & Arabic
- Education & training
This workflow uses the shared Eye Exam Simulator. The button opens the existing examination tools.
Your first practice session
- Observe a normal response when illuminating each eye.
- Choose right-eye RAPD and alternate the light.
- Repeat with left-eye RAPD and explain the response of both pupils.
Common mistakes to avoid
- Looking only for unequal pupil size.
- Changing illumination timing instead of keeping the comparison consistent.
For education and training only. Pupilla is not a medical device and must not be used for diagnosis or treatment decisions.
Understand the principles
RAPD and the swinging flashlight test
A relative afferent pupillary defect (RAPD), or Marcus Gunn pupil, means one eye sends a weaker light signal to the brainstem than the other. It is found with the swinging flashlight test: when the light swings from the healthy eye to the affected eye, both pupils dilate instead of staying small. An RAPD points to asymmetric optic nerve disease or extensive retinal damage, and on its own it does not make the pupils unequal in size.
Anisocoria: Horner syndrome, Adie tonic pupil and third nerve palsy
Anisocoria means the pupils are unequal in size. The key first step is to compare them in bright light and in dim light. If the difference is greater in the dark, the smaller pupil is abnormal because it cannot dilate — think Horner syndrome. If the difference is greater in bright light, the larger pupil is abnormal because it cannot constrict — think third nerve palsy, Adie tonic pupil or a pharmacologically dilated pupil. A difference of about 1 mm or less that is the same in light and dark is usually physiological.
Try a virtual patient
Teaching examples in the exam simulator. Observe and explain the signs before comparing cases.
Questions about this simulator
What can I practise with the RAPD & Swinging Flashlight Test Simulator?
Practise the swinging flashlight test and observe a relative afferent pupillary defect on a virtual patient. Compare right- and left-eye responses with the normal examination.
Do I need to install software or create an account?
Open the simulator free in a modern browser without installation. An account enables supported saved progress and results; coverage varies by module.
Can I use a phone or tablet?
You can access it in modern phone and tablet browsers. A larger screen gives diagrams and controls more space; performance depends on the device and browser.
Does this replace clinical training or patient diagnosis?
For education and training only. Pupilla is not a medical device and must not be used for diagnosis or treatment decisions.
References & further learning
Sources for the teaching principles. Listing a source does not imply its institution endorses or validates this simulator.