Under normal circumstances, when a dog normally falls asleep, its eyelids tremble. After falling asleep, the eyelids will not move, and they may also roll their eyes. For dogs, this is mainly to block light and is a biological instinct. Just like when a person is sleeping, if you open its eyelids, you will see that its eyes are white. This is only true for people or animals who are sleeping.

Of course, a dog rolling its eyes may also be a sign of other abnormalities. For example: If a dog suffers from eye disease, it will roll its eyes abnormally when sleeping. Or it may have been infected with parvovirus or canine distemper. These conditions may cause the dog to roll its eyes while sleeping. But it is worth noting that normal dogs will not have other abnormal symptoms when they roll their eyes. Dogs that roll their eyes because of illness may also develop other symptoms. For example: runny nose, convulsions, tears from the corners of the eyes, abnormal secretions from the corners of the eyes, etc. When you discover these abnormalities, you should start to pay attention to them and take your dog to the hospital for diagnosis and treatment immediately.