Dominant Eye Test: How to Tell Which Eye is Dominant

What is a Dominant Eye?

A dominant eye refers to the eye that is generally more favoured by the brain and is often used to perform functions over the other. According to a paper by Moreno, Capdevila and Losilla, a person’s dominant eye is usually the brain’s preference for input to the visual cortex, and can relay information more accurately than a non dominant eye. According to the American Academy of Ophthalmology, a dominant eye is not necessarily the eye with the best vision. A dominant eye will generally not have any bearing on overall vision or eye health, however, it may be beneficial in performing certain tasks like photography and sports such as golf and baseball. A dominant eye can be either the left eye or the right eye, and can sometimes match a person’s dominant hand, but this is not always the case.

What is a Dominant Eye Test?

A dominant eye test is a test that a person can take to determine which eye is dominant. Finding out which eye is dominant is not always a part of a standard eye test with an optometrist, as knowing which eye is dominant does not always relate to overall vision quality or eye health.

According to an article in the Hong Kong Journal of Ophthalmology, a dominant eye test may be used by an optometrist if the clarity of vision can't be balanced by refraction. A person may take a dominant eye test if they are a photographer, or playing sports such as baseball and golf, as this may help with performance. According to the American Academy of Ophthalmology, knowing which eye is dominant may also help with certain eye care such as treating strabismus and amblyopia.

How to Tell Which Eye is Dominant?

There are three main tests a person can take at home to determine which eye is dominant, including the hole-in-a-card test, miles test, and a point test. An optometrist may use different methods to determine eye dominance if needed. The at home tests to determine which eye is dominant are listed below.

• Hole-in-a-card Test: A hole-in-a-card test uses a card with a hole cut in the centre to determine eye dominance.
• Miles Test: A miles test uses the hands, crossed into a triangle shape in front of the face, to determine eye dominance. 
• Point Test: A point test involves pointing the index fingers at an object and closing each eye to determine which eye keeps the object in focus, determining eye dominance.

1. Hole-in-a-card Test

The hole-in-a-card test is a test to help determine which eye is dominant. To conduct this test, begin by cutting a hole in the middle of a piece of card or paper. The hole should be around the size of the eye. A person will then hold the card out in front of their face and look through the hole, with eyes open, at an object in the distance. The person will then slowly bring the card closer to their face. The eye that the card is in front of will be the dominant eye.

2. Miles Test

A miles test is a simple test using just the hands, to help determine eye dominance. To conduct a miles test, a person will put their arms out in front of them, crossing their hands to make a triangle shape. A person will then pick an object in the distance and look at it through the triangle. The next step is to close each eye alternatively. If the object moves out of the triangle, then the eye being used is the non-dominant eye.

3. Point Test

A point test is a test that helps to determine eye dominance. A point test is simple and involves a person clasping hands together with the index fingers out straight. A person will point the index fingers at a distant object, in front of the face. A person will then close each eye whilst looking at the object. If a person closes an eye and the fingers remain pointed at the object, this is the dominant eye.

What is the Relation Between Eye Dominance and Handedness?

The relation between eye dominance and hand dominance, usually referred to as left or right-handedness, is not fully understood and is the subject of much scientific research. Eye dominance may, but not always, correspond to a person’s hand dominance. The relation between eye and hand dominance is an important area of study, as understanding it may help to improve hand-eye coordination, which is an important part of daily activities, as well as sports and photography.

Why is a Dominant Eye Test Important?

A dominant eye test is generally important for those who may find their performance enhanced by knowing their dominant eye, such as athletes or those who do photography. Knowing what your dominant eye is, is not always important in regards to eye health or daily activities. However, an optometrist may conduct one to help with treatment for certain eye conditions such as strabismus or amblyopia. The importance of a dominant eye test for athletes, for shooting purposes and photography is listed and explained below.

• Dominant Eye Test for Athletes: Dominant eye testing is important for athletes as it can help improve aim and overall performance.
• Dominant Eye Test for Shooting Purposes: A dominant eye test for shooting purposes may be beneficial as it can help improve aim.
• Dominant Eye Test for Photography: A dominant eye test for photography or photographers may be important as it can help with alignment and framing.

How is a Dominant Eye Test Done in Eye Clinics?

An optometrist or eye care professional may use a lens fogging technique during a refraction test, to test accommodation and help determine which eye is dominant. Lens fogging involves having a patient focus on a distant object, with a plus power lens over the eyes. The lens will make the object appear blurry. The optometrist or eye care professional will alternatively change the lens over each eye, with the patient encouraged to determine in which eye the blur is more noticeable. The eye that is blurry and less comfortable will be the dominant eye, according to the paper Monovision Correction Preference and Eye Dominance Measurements, published in the journal Translational Vision Science and Technology.

Does the Dominant Eye Have Better Vision?

A dominant eye does not necessarily have better vision than a non-dominant eye. A dominant eye is the eye that the brain favours to complete visual tasks, which is not always the eye with better visual acuity.