WILTIMS #498: O.o

TIL: Parinaud's syndrome is a weird collection of neurological eye exam findings usually caused by a tumor in the pineal or midbrain regions of the brain. The most prominent symptom is the inability to look up. The eyes can still move up, but the patient can't look up voluntarily. This can be demonstrated with a "doll's head test" where you have the patient relax looking straight ahead when you suddenly rotate their head forward. Another part of the brain controls this reflex, so the eyes will roll up in their sockets just like a doll's, before reverting. If one of the eyes is more affected than the other, then the patient may have double vision from one eye being stuck lower than the other.

Image from here

The next sign of Parinaud's has a fun name: pseudo-Argyll Robertson pupils. This is when the pupils are dilated (the black of the eyes is larger than normal) and they won't constrict when you point light at them. You can still make them constrict though if you use a trick. When you look way off in the distance, your pupils dilate a little; when you look at an object really close to your face (like your nose), the pupils constrict a bit. This reflex should be preserved in patients with Parinaud's syndrome. Again, if one eye is more affected than the other then the pupils may be different sizes at rest.

Then we have a whole bunch of related problems with moving the eyes in unison. These patients have a problem when you have them rapidly look at an object close or far away from them. Normally, you want both eyes to move in unison and stop at the precise spot to properly focus on an object. When that doesn't happen (e.g. one eye moves faster than the other, or overshoots the target, or stutters to the spot rather than moving smoothly), the patient will experience temporary double vision. Often these patients will have a particularly weird problem called convergence retraction nystagmus, where the eyes will retract into the socket when you have them look at their nose. This is because the ocular nerve is getting confused and instead of using some of the eye muscles to look in a direction, it contracts all of them. This pulls the eyes inward. See the GIF for an example!

Image from here

Lastly we have Collier's sign, marked by bilateral upper eyelid retraction. This makes the patient look a little "bug-eyed," but specifically results in an uneven amount of white above the irises. For an example, take a gander at this fantastically mustachioed man on the left. He has white visible above the irises of the eyes; for comparison, see that neither of the persons pictured above have white visible there. If patients with Collier's sign could look up (which they usually can't, as per exam finding #1, above) the eyelid would match the movement of the pupil and recede even further up.