What is Dominant Eye?

In most cases, when both two eyes work well and have the same vision, the dominant eye is the "dominant eye". In the visual part of your brain, it will give priority to analyzing the image received by your dominant eye, and more accurately convey information about the location of the object. But sometimes, "dominant eye" is used to describe eyes with normal vision and normal function in cases of amblyopia and strabismus.

Find out your Dominant Eye

Here is a simple main eye test to find out which eye is your main eye:

1. Extend your arms in front of you and create a triangular opening between your thumb and index finger by placing your hands together at a 45-degree angle.
2. Open your eyes and place this triangular opening on a distant object, such as a wall clock or door handle.
3. Close your left eye.
4. If the object stays centered, your right eye (the one that is open) is your dominant eye. If the object is no longer framed by your hand, your left eye is your dominant eye.

This is another simple dominant eye test:

1. Extend one arm and keep the thumb of that hand in an upright position. (Or you can use index finger instead of thumb.)
   
2. Keep your eyes open and focus on the distant object, and place your thumb on the object. (If your thumb seems to be partially gone, don’t worry, this is normal.)
3. Alternately close one eye at a time.
4. When the other eye is closed, the eye with your thumb directly in front of the object is your dominant eye.

Although the dominant eye test is simple and usually accurate, it may be affected by the dominant hand and other non-visual factors. But in most cases, the simple main eye test above can accurately find your main eye.

Reference：All About Vision