It could just be allergies, or his eye got irritated by something. Can you see anything in his eye? Try some over the counter eye drops like Refresh from the drugstore and put some in his eye. It will help flush it out if something is in his eye, and will help with the redness. Keep an eye on it, just in case it is an eye infection starting, it doesn't look like one now, but could be one starting. If it does turn into an infection or gets worse, have the vet look at it. Hope it's to hing serious.
He is so darn cute! I would think environmental allergies could cause this, but not necessarily food. Monica gave you great info... keep close watch and any additional change have your vet check it out
Something is certainly off, when it comes to the eyes I would get him to the vet to check it out just in case he scratched it, a small scratch can turn into an ulcer very quickly, and are very painful.
Our boy Abbott has had eye issues since he was about 6 months.He has allergies and has had two entropion surgeries.His eyelids roll in causing his eyelashes to lay on his eyeball, not much fun for them or their parents.Just keep putting drops in and keep can eye on him..no pun intended. Lok