The Miles Test (Testing Dominant Eye)
The client extends both arms, brings both hands together to create a small opening, then with both eyes open views a distant object through the opening (a card with a hole in the center can also be used, this is known as The Dolman Method). The client then alternates closing the eyes. The eye that remains open and the object does not move from vision can be considered the dominant eye.
To confirm have the client slowly draw opening back to the head to determine which eye is viewing the object. The opening will move towards the dominant eye.