We all have a preferred or dominant eye just as we all have a preferred or dominant hand. In most cases, the dominant eye corresponds with the side of the dominant hand. Thus, if you are right-handed, chances are that your dominant eye is also the right eye. Of course, this is not always true. You can find out which is your dominant eye by doing this simple test.
Stretch out both hands with the palms facing away from you. Overlap the fingers and outstretched thumbs of both hands to make a coin size opening as shown.
With both eyes open, look at a distant object such as a wall clock through the opening formed. Keeping your hands and head very still, look at the object one eye at a time. YOUR DOMINANT EYE WILL BE THE EYE THAT SEES THE OBJECT.
Usefulness Of This Test
Knowledge of your dominant eye is useful if you wish to perform well in activities that depend on the use of one eye. Examples include using monocular instruments like the telescope or microscope, sporting activities such as archery, shooting, darts and billiards and when using `mono-vision’ contact lenses to overcome middle-age farsightedness where the dominant eye is corrected for distance and the non-dominant eye for near vision.