This cat looks very wide eyed doesn’t it? Wide pupilled one should say, if such a word exists! The cat can see but has no pupillary light reflex at all. It is somewhat constipated too, though sometimes rather the opposite (enough said!) and regugitates as well. What is your diagnosis and how might you confirm it?.
The cat has feline dysautonomia or what we used to call Key Gaskell syndrome. I say ‘used to’ as I haven’t seen a case since 1989 just after I qualified. Using the parasympathomimetic pilocarpine caused a very rapid and complete miosis, through the aceylcholine receptor upregulation at the motor end plate by Cannon’s denervation hypersensitivity. Here is the cat 5 minutes after applying pilocarpine to its right eye….
…and here it is after 10 minutes with a really highly miotic pupil…..
Quite what causes this condition is unclear, though as with grass sickness in horses there may be a link with Botulinum toxin. The cat has a megaoesophagus fitting in with the autonomic dysfunction. Have you seen one of these – there are one or two reported in the literature but maybe many more out there – do let me know if you’ve seen one!