Hydroxyamphetamine Test

Hydroxyamphetamine test.png

Hydroxyamphetamine test for Horner syndrome.

A. Before drops administered (suspected right Horner syndrome).

B. After drops administered. Note the dilation of both pupils. This indicates an intact 3rd-order, postganglionic neuron and localizes the lesion to the 1st-order (central) or 2nd-order (preganglionic) neuron.

Image credit: Modified from clinical images courtesy of Lanning B. Kline, M.D. American Academy of Ophthalmology. Used with permission for educational purposes.