There are several reasons why you need to know which eye is more dominant. Besides being interesting, it's also useful for doing activities that use one eye, such as when using a microscope, telescope, or focusing the camera without a viewing screen. Your ophthalmologist may also want to determine your dominant eye for certain treatments. You can easily find out yourself at home. But please note, the results may vary depending on the distance you test it.
Method 1 of 2: Evaluating Your Dominant Eye
Step 1. Try a simple pointing test
With both eyes open, point your index finger at a point in the distance. Close one eye, then switch and close the other eye. Your finger will appear to move or move away from the object when one eye is closed. If the finger doesn't seem to move, then the eye you are closing is the non-dominant eye.
Another variation of the test is to stretch your arms far out in front of you and form a triangular hole with your fingers. Through this hole, stare at an object about 3 meters away with both eyes open. Without moving, close one eye, then the other. Objects will appear to move, possibly exiting the “triangle window” when you close one eye. If the object moves, you are looking with the non-dominant eye
Step 2. Perform the “Hole in Card - Remote” test
This test tests which eye you use to focus on an object 3 meters away. You can easily do it yourself at home.
- Make a hole in a sheet of paper about 4 cm in diameter. On the second piece of paper, write a letter 2.5 cm high.
- Glue the paper with the letters on the wall at a level that is at eye level. Measure the distance as far as 3 meters.
- Stand 3 meters away from the letters on the wall. Hold the perforated paper with both hands fully extended forward. Your hands should be parallel to the floor.
- Look at the letters on the wall through the holes in the paper. Once you see the letters, have a friend cover one eye first, then the other. Do not move or change position. The eye that can see the letter is your dominant eye. If you can see with both eyes, there is no dominant eye in this test.
Step 3. Perform the “Hole in Card - Close Range” test
This test is similar to the Hole in the Card - Distance test, but tests which eye you use when focusing at close range. You can also do this quickly and easily using objects at home.
- This test can be done using a thimble, shotgun, or similar object at home. Write a letter 4 mm high and wide on a piece of paper. Glue this letter to the inner base of the thimble/slot.
- Cover the thimble/slot with paper or a thin sheet of aluminum. Use rubber or tape to attach it. Make a small 4mm hole in the paper or aluminum sheet. The hole should be directly above the letter, so when you peek through the hole, you'll see the letter.
- Place the thimble/slot on the table and look down so you can see the letters. Do not touch the thimble/shot or press your eye on the hole. Your head should be 30 – 60 cm.
- Don't move your head when you see the letters. Have a friend close one eye, then the other. The eye that can see letters is the dominant eye. If both eyes can see the letters clearly when one of them is closed, you do not have the dominant eye for this test.
Step 4. Perform a convergence test (focus on one point)
This test tests which eye is dominant at very close range. The results may differ from the results of other tests.
- Take a ruler. Write a letter on a piece of paper. The letters must be 4 mm high and wide. Glue the letters to the ruler so they don't change position.
- Hold the ruler in front of you with both hands. The letters should be at eye level. Focus on the letters. Slowly, with both hands, slide the ruler straight up toward the nose.
- Stop when one eye can no longer focus on the letter. That's the non-dominant eye on this test. If both eyes remain focused until the ruler touches the nose, there is no dominant eye in this test.
Method 2 of 2: Using Information
Step 1. Improve your skills
If you play a particular sport or have a hobby that makes you dependent on only one eye, consider using the dominant eye. But remember, eye dominance can vary depending on distance. So make sure you consider the most relevant eye dominance test results and use that eye instead of the non-dominant eye. Your dominant eye may be on the opposite side of your dominant hand or foot. Activities that make you have to rely on one eye include:
- Aim with a gun
- Focusing on an object on a camera that doesn't have a large preview screen
- Seeing with a telescope or microscope
Step 2. Discuss this information with your ophthalmologist
Knowing your dominant eye is especially important for people who wear monovision contact lenses (eye correction, one for close-up and one for long-range). If your doctor prescribes monovision contact lenses, he or she will likely test your eye dominance as well. There are two types of monovision lenses:
- Monovision contact lenses. People who wear monovision contact lenses have a prescription lens for distance vision in their dominant eye and a lens for reading in the non-dominant eye.
- Modification Monovision. The user wears a bifocal or multifocal lens in the non-dominant eye and a lens for distance vision in the dominant eye.
Step 3. Ask your eye doctor about exercises to strengthen your eyes
If you feel that one eye is too weak, you may be able to strengthen it by doing exercises. But always consult a doctor before starting any exercise to avoid eye strain. Your doctor may recommend:
- Convergence exercise. In this exercise, slide the ruler or pen slowly toward your nose. When the object starts to look double, stop and refocus until the object seems to come together again. If necessary, move the pen away a bit and try again.
- Practice focusing your non-dominant eye up close at reading distance, then move it away. Ask your doctor how long you need to maintain focus at different points. Then close your eyes to relax them for a minute.