What is a dominant eye?
You look at the world with two eyes, but when you need to line something up, such as a sight with a target or a finger with a light switch, your brain trusts one eye's view a little more. That eye is your sighting-dominant eye. It is a preference in how the brain combines the two images, not a sign that one eye sees better. Your dominant eye can even be the one with weaker vision, the eye that needs the stronger lens. How sharply each eye sees is a different question, which the eye test checks.
Most people are right-eye dominant. In one study of 103 mostly young adults, Ehrenstein, Arnold-Schulz-Gahmen and Jaschinski (2005) found a right-eye preference in sighting tests in about two thirds of them (68%). Eye dominance is related to handedness, but they do not always match: plenty of right-handed people are left-eye dominant.
How the test works
The test walks you through two classic methods, one step per screen. You need both hands free and a small target. On a computer, step back 2–3 meters and use the red dot on the screen. On a phone, use a small object at least 3 meters away, such as a light switch or a door handle.
Hand triangle (Miles test). Walter Miles described this method in 1930. Stretch both arms out, put your hands together so your thumbs and forefingers form a small triangle, and look at the target through it with both eyes open. Then close your left eye: does the target stay inside the triangle? Open both eyes, center the target again, close your right eye, and answer the same question. Because the triangle is lined up with one eye only, the target stays in place for the dominant eye and jumps out of the opening for the other.
Pointing finger (Porta test). The Italian scholar Giambattista della Porta wrote about this one in 1593. Point your index finger at the target with both eyes open, then close each eye in turn. The finger stays on the target for the dominant eye and seems to jump to the side for the other.
For each question you can answer Yes, it stayed, No, it jumped or Not sure.
How the result is worked out
For each method, the eye that kept the target in place is the dominant one. If the target stayed for both eyes, jumped for both, or you were not sure, that method counts as unclear.
- Both methods point to the same eye: that is your result, with the note that both tests agreed.
- One method is clear and the other unclear: the result follows the clear one, and the card suggests repeating once to confirm.
- The methods disagree, or both are unclear: no clear dominant eye this time. Some people have only weak sighting dominance. A farther target, a smaller triangle and resting your elbows usually make it clearer.
Why it matters: shooting, photography and sport
- Shooting and archery. If you are right-handed but left-eye dominant (cross-dominant), your eye and your aiming hand are on different sides. Shooters solve this by aiming from the side of the dominant eye, by closing or blurring the dominant eye, or by putting a small piece of tape on the shooting glasses. Knowing your dominant eye before you learn saves bad habits. On a screen, aiming depends more on hand–eye coordination, which the aim test measures.
- Photography. Most people find it more natural to look through a viewfinder with their dominant eye.
- Ball sports and golf. Batters, players lining up a putt and pool or snooker players often adjust head position so the dominant eye sits over the line of the shot.
- Contact lenses and eye surgery. In monovision, where one eye is set for distance and the other for near, eye care professionals usually test which eye is dominant before choosing which eye gets which focus.
Limits of the test
This test relies on what you notice and on keeping your hands still. Glasses that are much stronger in one eye, tiredness or looking at the target from an angle can change the answer. Dominance can also vary with the direction you look. Repeat the test on another day if the result was unclear.
When to see an eye doctor
Eye dominance on its own is normal and needs no treatment. See an eye doctor if you see double, if one eye drifts inward, outward or upward, if you often close one eye to see clearly, or if vision differs a lot between your two eyes. In children, a turning eye or a strong preference for one eye should always be checked, because early treatment matters for a lazy eye (amblyopia).
More checks like this are collected on our vision tests page.
Sources
- Ehrenstein, W. H., Arnold-Schulz-Gahmen, B. E., & Jaschinski, W. (2005). Eye preference within the context of binocular functions. Graefe's Archive for Clinical and Experimental Ophthalmology, 243(9), 926–932.
- Miles, W. R. (1930). Ocular dominance in human adults. Journal of General Psychology, 3(3), 412–430.
- Della Porta, G. B. (1593). De refractione optices parte libri novem. Naples: Salviani.
Frequently asked questions
How do I find my dominant eye?
Make a small triangle with your hands, look at a distant target through it with both eyes, then close one eye at a time. The eye that keeps the target inside the triangle is your dominant eye. This page guides you through that and a second pointing test.
Is it normal to be left-eye dominant?
Yes. Studies suggest roughly two thirds of people are right-eye dominant, so about one in three prefers the left eye. Neither is better.
Does my dominant eye see better?
Not necessarily. Eye dominance is about which eye the brain uses to line things up. Your dominant eye can have the weaker vision or the stronger glasses.
What is cross-dominance?
Cross-dominance means your dominant eye and your dominant hand are on different sides, for example right-handed and left-eye dominant. It matters most in shooting and archery.
Can eye dominance change?
It is usually stable, but it can vary with the direction you look, after eye surgery, or when vision in one eye changes a lot.
Why did the two methods give different results?
It usually means your dominance is weak or your hands moved a little. Use a target at least 3 meters away, make the opening small and rest your elbows, then repeat.