.... revisited, again, for the third time. Not that I'm complaining or anything, it seems Horner's is quite common. With over 70 million dogs in the US and 4 million in Canada, I would imagine that a significant number have been afflicted with Horner's syndrome at some point in their life. Have you heard of this syndrome? Has your dog or cat (or you) had Horner's? If so, tell me about it. Any questions? I'll try to help you out the best I can.
PS: See my post "Iranian kisses woman's breast," and the comments. By golly, I've been branded a racist.
A woman with Horner's syndrome (see previous two posts for photos of cat with Horner's).
Addendum: The eyes of two different colors, called heterochromia, is NOT part of Horner's syndrome. Note the small pupil and droopy eyelids. In cats and dogs, we'd also see the 3rd eyelid protruding. A sunken eyeball is often a subtler sign of Horner's.