Several signs show that a dog feels uncomfortable: head turn, look away, hurried breathing.
Many dogs treat straight look as a threatening sign. That's why, in the order to show friendly attitude and intentions, they look away and close their eyelids a little. This way their look becomes "softer". For example, your dog uses this sign when it needs to look at something but at the same way avoid threat expressing.
You may use this sign of calming. With its help you may train eye contact with your dog. Making your look softer you will not make threatening impression for your dog.
If you lay down to the floor or ground and your eyes are at the same level as
dog's eyes, it may seem to a dog that you are threatening it. Stand up
and look at a dog down from the top. Then your look is softer and a dog
calms down.