Can canines communicate with each other using gaze direction?
It is hypothesized that the starkness of white sclera against darker colors of the pupil and iris is a unique mutation in primates that have become prevalent in human beings because it enhanced our ability to communicate with other humans and animals, including dogs, by more clearly communicating where we are looking.



However, it has not yet been established that dogs use this communication with each other, communicating more commonly with other means such as body language, head direction, vocalizations, etc. Some dogs, especially domesticated ones, do have white sclera and it is proposed that this is due to unintentional selection by humans who have a preference for such features. 

 

What is extremely fascinating is that this 'mutation' occasionally occurs in chimpanzees and apes, too, but has not become prevalent in their respective populations.



Sources:


Secret Life of Dogs- BBC Film
Do the Eye Have It?-Academia 
Common feature in domesticated dogs-CARTA
Juvenile features-NIH