It’s RITE time–let’s talk eponyms! But first, what’s this called? (Answer after the jump).
In morning report today, we discussed Adie’s (or Holmes-Adie) tonic pupil. This is thought to be due to a lesion of the ciliary ganglion and is also associated with absent sweating and absent reflexes. Here’s a link to an article on it and here’s a link to a cool video of a slit lamp exam in such a patient (you have to click on one of the video format icons below the screen shot to start the video). Around minute 3:30 of the video, the examiner shows how the pupil reacts much better to near than to light (light-near dissociation). This is because there are many more fibers serving the accommodation reflex than the light reflex, allowing the former to be better preserved in the setting of ciliary injury.
Argyll Robertson pupils also exhibit light-near dissociation, but these pupils are small and grossly irregular bilaterally, not large, circular (except for the sectoral abnormalities seen on slit lamp), and unilateral like Adie’s pupil. It is classically associated with neurosyphilis, which explains it’s other moniker, prostitute’s pupil–they accommodate but don’t react. Here’s a video of this. Tertiary syphilis is rare these days, and thus so are Argyll Robertson pupils.
Finally, let’s throw in the Marcus-Gunn pupil. This is due to an afferent pathway lesion, resulting in paradoxical dilatation of the pupil in the affected eye when a flashlight is swung from the good eye to the affected eye. This video demonstrates is beautifully (again, you have to click on one of the icons in the middle of the page to start the video–there’s no screenshot of the video on this webpage).
(The picture above shows heterochromia. There are a few causes of this, but one interesting cause (obviously not affecting the person in this picture) is congenital Horner’s syndrome. Sympathetic input is needed to cause the iris to go from blue (at birth) to brown, so in addition to the typical Horner’s findings, in a congenital case the eye stays blue).