if its one eyed cold debbie, you will see slight bubbles on the bottom eyelid ,[if theve been fighting it will just show redness, swelling ] if it is one eyed cold it could get worse , but amazingly enough the frosty mornings are the best for the birds , this kills off a lot of nasties, [an old fashioned way,, was to put a clean spit :X not from a smoker , a childs is the best , this contains natural antibiotics which can help cure this ,,,yuc,, but true ;D,,,,,the old garlic in their water is a good preventative ,,for many things