I've always wondered if having different iris colors, (eye colors) may have any advantages or disadvantages on ones vision. Specifically regarding the effects of light.

Personally, I have troubles being out in the bright sun without sunglasses. My girlfriend on the other hand does not share this issue. Coincedentally my eyes are a light blue and hers are brown. After realizing this, I began to notice a trend when it comes to blue eyed people having this same issue.

So, on a bright day, does a person with blue eyes have a higher sensitivity to the light than their darker counterparts? Thank you.

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    $\begingroup$ I don't have time to do proper research and give a nice answer, but here is an answer from an unverified source. By unverified I mean I didn't check the credentials. It seems like a pretty good answer though. $\endgroup$ – SolarLunix Jul 25 '15 at 21:14
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    $\begingroup$ @SolarLunix "when melanin develops, it creates a protective filter that reflects the light back out of the eye"??? REFLECTS? $\endgroup$ – Ilan Jul 26 '15 at 11:59
  • $\begingroup$ @Ilan it's the same principle that makes the sky look blue from what I understand. $\endgroup$ – SolarLunix Jul 26 '15 at 13:50

Firstly, note that "eye color" is actually iris color.

The person with a lighter iris will have more straylight compared to person with brown iris:

enter image description here

The graph represents Intraocular straylight of the age-matched groups. Participants with light-blue-colored iris showed significantly higher values for intraocular straylight than those of the other groups.

Persons with light-blue-colored eyes have significant higher IOSL (intraocular straylight) values than persons with darker-colored irises (blue-grey, green-hazel, and brown). Light-blue-colored eyes had 0.07 to 0.08 log units higher IOSL values, which is an increase by a factor of 1.2. In regard to CS (contrast sensitivity), subjects with light-blue iris color showed also lower CS values than subjects with other iris color.

Edit: The study concluded that in people with blue irises, IOSL was significantly higher. Although IOSL did not affect best-corrected visual acuity (e.g. visual function based on a standard letter chart test at the optometrist), it did affect contrast acuity, meaning that folks with blue eyes had more difficulty assessing contrast differences (e.g., telling apart two grays with a slightly different brightness).

Christian Nischler & al. Iris color and visual functions. Graefes Arch Clin Exp Ophthalmol (2013) 251:195–202.

  • $\begingroup$ Thanks for the answer! Seems like a fair study aswell. All european participants but other than that I would say pretty unbiased. Also, appreciate the iris tip aswell, not always on my "A" game when it comes to adding proper jargon. $\endgroup$ – AstroMax Jul 27 '15 at 21:30
  • $\begingroup$ Too bad though... kinda wish the study would have come to a more neutral conclusion. Guess light blue eyes aren't so great after all... $\endgroup$ – AstroMax Jul 27 '15 at 21:49
  • $\begingroup$ I added the functional consequence of straylight. +1 $\endgroup$ – AliceD Jul 28 '15 at 0:39

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