Does the color of the irises affect eyesight (color perception, vision in the dark, etc.)?

07 Dec Does the color of the irises affect eyesight (color perception, vision in the dark, etc.)?

To a small degree, Yes. The iris is a muscle sphincter that opens and closes to regulate the amount of light that passes through the pupil into the eye. The iris doesn’t actually come in different colors; there is only a single brown pigment (for everybody) that covers its posterior surface. The variations in eye color that we refer to (blue, green, hazel, brown) are more a matter of how thick the iris muscle is. A thick iris is brown and serves to screen out strong light just like a heavy brocade curtain would. A thin iris can be more like a lace curtain -while it does help, there is still a lot of light that can go right through. The apparent colors are due to the scattering of white light differently according to wavelength (like the sky as a matter of fact).

So while visual acuity is not affected by the different colors of the iris, glare and discomfort in strong light can be an issue at times.

_Written by J. Trevor Woodhams, M.D. – Chief of Surgery, Woodhams Eye Clinic