It is likely that, at some point in your life, you have already come across the term dominant eye. As the name suggests, it is the one that the brain prioritizes to process visual information.
HAS CNNthe ophthalmologist Tiago César Pereira Ferreiraexplains that the dominant eye is mainly responsible for the alignment of objects in the field of viewthus playing a fundamental role in activities that require visual precision, such as.
“This dominance is not necessarily related to the quality of vision, but rather to a neurological preference, where the brain favors the information sent by one of the eyes, even if both have the same visual acuity”, he says.
Why identify the dominant eye?
According to the professional, identifying the dominant eye is important in several clinical and practical situations. “In refractive surgery, for example, it is essential in planning techniques such as monovision, where one eye is corrected for distance vision and the other for near vision”, he says.
“When adapting multifocal or monovision contact lenses, knowing the dominant eye guarantees better visual results and comfort for the patient”, he states.
When it comes to practicing physical activities and sports that require precision, such as sports shooting and photography, identification is also crucial for correct eye alignment.
“Furthermore, in , knowing the dominant eye can be decisive in personalizing diagnoses and treatments, helping to understand how the patient compensates for any visual difficulties”, he adds.
Do all people have a dominant eye?
Tiago emphasizes that everyone has a dominant eye, regardless of whether they have it or not. Ocular dominance is a natural neurological characteristic, not a pathological condition.
“However, in people with significant visual changes, such as marked differences in refraction or amblyopia, this dominance may become more evident, as the brain tends to favor the eye with better visual capacity or the one that provides greater viewing comfort,” he explains. .
It is also important to emphasize that it is possible for a person do not show clear ocular dominance. The condition, however, is known as alternating dominance. “In this case, the two eyes may share dominance evenly, or the brain’s preference may vary depending on the task performed,” he comments.
“This diagnosis is rare and may be more common in people with exceptionally balanced binocular vision, or in individuals who have suffered significant changes in vision in one eye, such as after surgery or trauma. Some neurological conditions can also influence the absence of fixed ocular dominance”, he states.
How to do the dominant eye test at home?
Among the simplest methods for identifying the dominant eye is the triangle test. For that:
- Extend your hands in front of your face, bringing your thumbs and index fingers together to form a small triangle;
- Choose a fixed object at a distance, such as a switch, and align it within the triangle with both eyes open;
- Close one of your eyes;
- If the object remains visible within the triangle, the open eye is dominant;
- If the object “leaves” the triangle, the dominant one is the eye that was closed.
The second alternative is called hole test. Therefore:
- Take a paper with a small hole in the center and look through it at a distant object, keeping both eyes open;
- Alternately close each eye;
- The eye that keeps the object visible in the center of the hole is the dominant one.
Be careful with home tests
When performing the dominant eye test, it is important to observe some precautions to ensure the accuracy of the result. “The environment must be well lit to avoid visual interference, and the focus must be completely on the target object, without distractions”, says Tiago.
“Both eyes must remain open at the beginning of the test, and closing one of the eyes must be done alternately. The distance between the observer and the target object must be adequate, preferably greater than 3 meters, to avoid bias in visual alignment”, he guarantees.
“Repeating the test a few times is also recommended to confirm the result and eliminate possible errors caused by distractions or momentary misalignments”, concludes the ophthalmologist.
