Common causes of Horner's syndrome in horses include cervical trauma, guttural pouch infection, neoplasia, focal infections, foreign bodies (“choke”), periorbital disease, perivascular injections and carotid artery ligation. This guy had been getting IV gentamicin (for a pasture injury to his leg that required stitches) so most likely from the IV. Super interesting, hopefully he makes a full recovery, but in some horses it can last for months #horners #syndrome #hornerssyndrome #fyp #horse | Ash

Horner syndrome: Video, Causes, & Meaning | Osmosis