Pets can get allergies too. Maybe the scent of a new laundry soap or perfume? If the eye has a lot of discharge or becomes swollen shut, that may be an eye infection. Then you'll have to go to a vet to get antibiotics. Usually human and pet viruses are not contagious with each other, but there are some that can be so make sure to constantly wash your hands and any bedding or pillows they are sitting on.