A: Not everybody does this, according to a professor of neurobiology and behaviour at Cornell University, but those who do do so because of a phenomenon called binocular rivalry.
If you look through a sight with the left eye alone, what you see is not identical with what you see with the right alone, and the two images compete rather than blending.
For example, if the left eye is shown only vertical lines and the right eye only horizontal lines, you might think you would see a screen pattern, but in fact you would see patches of vertical lines intermingled with patches of horizontal lines.
Some people can mentally suppress the competing image, but some find it uncomfortable. So they close one eye.
When aiming at a target, most people tend to use the dominant eye, which generally but not always has better vision. If the eyes differ in focal length, some may use one eye to aim at objects farther away and use the other for targets that are closer.
Published - September 17, 2024 02:25 pm IST
