Most people have a dominant eye that corresponds to their dominant hand. For example, if you are left-handed, you are more likely to have a dominant left eye. Right-handed people can also have a dominant left eye, but it is not as common.
Why Your Dominant Eye Is Important
Ocular dominance, or dominant eye, is when you use one eye more than the other, have better vision in one eye, or can fixate on something better with one eye. Knowing which eye is dominant can be important for performing activities that require you to focus on a target. These activities include:
- Using a telescope
- Using a microscope
Many people don’t realize they have a dominant eye until they’re given an eye exam to test which eye functions better. If you’re cross-dominant, meaning your dominant hand is opposite your dominant eye, you will likely need to make adjustments when playing certain sports such as golf or baseball.
Dominant Eye Testing
Ophthalmology clinics have equipment designed to test your eyes and will be able to give you the best results. The “+1.50D blur” test is commonly used by eye doctors to test for eye dominance. This test uses a series of lenses. An eye doctor will change the lenses and ask you what you experience.
If you want to try to figure out which eye is your dominant eye without a visit to the doctor, there are several easy tests you can perform yourself. These “home” tests are surprisingly accurate:
- Hole in the card test
- Point test
- Thumb test
The “hole in the card” test is the most commonly used test for determining a dominant eye. The test is performed by using a rectangular card with a small hole in it. You can do the test yourself by cutting a hole in an index card. Hold the card at arm's length in front of you and focus on an object on the other side of the hole. Slowly bring the card toward you until it touches your nose. The card should be covering one of your eyes – and that is your dominant eye. Studies have shown more people to have a dominant right eye.
Vision Conditions and Eye Dominance
Your eye doctor may need to assess which eye is dominant to make decisions about your eye health and treatment plans.
For example, monovision is when one eye is used to see objects far away and the other eye is used to see objects close up. Being able to see things at a distance is believed to be more important than seeing up close. Your doctor or clinician will test for the dominant eye and assign it to distance vision before doing surgery. For people using monovision contact lenses, it is important to know which eye is dominant so you put the correct contact in each eye. One contact will be for near vision and the other will be for distance vision. The contact for distance will be placed in the dominant eye.
Other vision conditions that will need a dominant eye assessment include:
Cataract surgery and other vision surgeries have been known to cause the dominant eye to switch. Usually, your eye surgeon can set which eye will be used for distance vision and which eye will be used for near vision. It is unknown why eye dominance sometimes changes after these surgeries.
If you are curious about which eye is your dominant eye, you can perform one of the easy at-home tests. Knowing which eye is dominant isn’t important unless you have vision problems, have hobbies that require you to focus on a target, or play sports.