My girls, Cecil and Brandy, both wake up in the morning with a little sleep in the corner of their eyes. I just wipe it away and they are fine for the rest of the day. I should note that when the sleep residue is a clump of gooey stuff, she has had an eye issue. One time she had a black eye and the other was some kind of infection. The vet gave me some eye goo to put in her eye twice a day and that took care of it. The normal sleep in the eye is just a small amount and not a clump of gooey puss.