If he is vomiting up everything what makes you think that chicken will stay down?
I think that it is necessary to follow up with your vet and make sure that he has no obstruction or mass in his abdomen causing the vomiting, or something metabolic such as kidney disease, liver disease, etc. Additionally, some eye problems and blindness can be caused by systemic diseases.
Your vet may not have all bad news for you.
Took my dog to the vet. His kidney reading was 14. Had to put him down. Very sad . Not the same without him in the house. we miss him terribly.
I will call the Dr. today. Thank You.