What does it mean when one eye sees a different color?
In respect to this, why does one eye look brighter than the other?
Depending on your age it could be because one eye is developing a cataract or a problem with the optic nerve. If it is a longstanding problem (since childhood) then it could just be a lazy eye.
Similarly, it is asked, does one eye see more red than the other?
If you show the colored light to only one eye (say by closing only one eye), only the red-responsive cone cells in that eye will adapt. If you open both eyes, the brain adjusts, and you only see one view of the world. However, if you look through one eye and then the other, you will be able to tell the difference.
They claim it's entirely possible that two people can look at the same object and have the same wavelengths hit their eyes, yet “see" different colors! Still others — called tetrachromats — may have a fourth photoreceptor that helps them see the full range of colors with greater sensitivity than the average person.