What about this: Look squarely in the bathroom mirror. Hold your head firmly against something to prevent movement. Close your right eye. Use a fine tipped dr

What about this: Look squarely in the bathroom mirror. Hold your head firmly against something to prevent movement. Close your right eye. Use a fine tipped dry erase maker to make a dot over your left eye's pupil. Then close your left eye and make a dot over your right pupil. Measure the distance between the dots. ?