Third eyelid swelling

Question
My snow shoe siamese has both eyelids swollen.  Not red but not retracting all the time.  I've taken him to the vet and he was tested for all knids of stuff and given a steroid/antibiotic/B12 shot.   But his eyelids are not better.  Could it be the cheap grocery store food.  I've never fed him anything more expensive, but he's only a year and a half old.  What about worms.

Answer
Certain types of worms show up in their stool or around their anus or vomit...

I really think you should keep your appointments with the vet since this is an ongoing eye issue

I really doubt that changing brands of food would show a miraculous difference (unless your vet specifically thinks its a food allergy)  But if it will make yourself feel better, you could switch to a more expensive brand.