I wear daily contacts most days but wear glasses once in a while. when i wear my glasses though my eyes become red and burn. why is that?

Dry Eye Syndrome: If you wear contacts they act as a moist sponge to retain water and keep your eye lubricated. When your contacts are out your eyes are succeptible to the drying effects of the air. Since the tear film is such a critical layer for eye health, I would recommend adding a supplemental lubricating eye drop (such as Systane Balance) two or three times a day. It is safe to use with your contacts too.