I normally have blue eyes, but sometimes they change to grey, what gives?

It can be a reflection of the color of clothing you are wearing. Start noticing what colors you wear when they are bright blue and when they are gray to see if you notice a pattern.

@chyna I usually wear black or very dark grey. Don’t have anything blue.

Next time, take note of the background lighting: sunlight, Fluorescent, LED, incandescent. The AWB, Average White Balance is different for each and that affects colors.

I went through all that charting stuff wth my dad. If there is a way to explain it, we never found it. We didn’t chsrt his diet, so if you want, you can look into that, but I believe it is just random, except for gray. My dad’s eyes changed mostly between brown and green, greenish blue. They only turned gray when he was really mad.
When I was in my teens, he and I were having a knock down drag out situation. His eyes were gray, and there was lots of shouting. He was about to give me a beating, but I had already decided I’d had enpugh. I spun around in his grasp, grabbed that belt from him, and told him NO! His eyes went instantly to this pale silver brey which made me think of the old blind master on Kung Fu. I never saw it turn so quickly, and never that color! I was faqscinated, and I just stared. I guess he took my prolonged gaze as the strength of my defiance. I just couldn’t look away from those eyes. Finally, I threw down his belt and stormed out. Now that I’m old and he’s dead, I can wonder what would have happened if I had said, “Dude, your eyes are like, silver, COOOOL!”
My story leads to the thought that maybe chemical changes could affect this, which can result from any number of things, not just some one thing. Perhaps a combination of things contribute. I just think it is cool.
I will keep an eye on the responses,(yes, I went for the pun) to see if anyone has anything solid on this.

Personally, I have never noticed any eye changes in anyone, unless they were wearing colored contacts. And I have never understood how people can have truly grey eyes. I’ve never seen those either.

Mine do the same thing. They are deep blue when I’‘m feeling all fired up, and pale blue when I’m without a night’s sleep. They get lighter in direct proportion to my energy level. They also change with the sky and sea. If the water is deep blue, so are my eyes. If the skies or seas are grey, so are my eyes. The only thing they don’t mimic is the beautiful green waters from Apalachicola to Pensacola. Then they’re just blue. Opiates make them a real spooky pale, pale blue, almost white.

@gailcalled “And I have never understood how people can have truly grey eyes. I’ve never seen those either.”

That’s a shame, they’re beautiful.

My blues will do the same thing of going from deep blue to bright blue depending on mood and ambient lighting.
I however have not noticed a change beyond that. I will keep a closer eye on myself now.

When I was little my mother used to tell me that my eyes would turn very dark brown. They’re normally green or light brown, depending.

While you are at it, keep track of your pupil size at the time. Are they large or small.

“When the pupil size changes, the pigments in the iris compress or spread apart, changing the eye color a bit.
Certain emotions can change both the pupil size and the iris color. That’s why some people say their eyes change colors when they’re angry or loving.”
Source

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@LuckyGuy I could try but I think calipers might be painful

lol

All you need is an estimate: Small, medium, large. Also note the light intensity: . bright , normal or dark .
I only care about absolute numbers when working with optics. Even then we usually round to the nearest 2mm : 2mm, 4mm, 6mm, 8mm .
That is important for night vision and sizing hand held optics like binoculars and spotting scopes.
I sized my Nikon binoculars to perfectly match my eyes (to the mm, of course) at twilight.

My eyes change colour, but I can’t believe it has anything to do with mood. That reeks of confirmation bias to me. I agree that it is likely due to ambient light and reflection of nearby colours.

Well, I noticed the eye color change a few times and everything was identical, same room, same mirror, same clothes, same lighting.

Did you check your mood at the time? Mood can change the size of your pupils, and based on what my mother used to tell me, even the color of the iris. I forgot to mention in my above answer that she said when I got mad my eyes got really dark brown/black.

It happens to me to some degree also. It has to do with lighting, make-up, what I am wearing, and the colors in the room. I always see my eyes as blue, but when my make-up is right, especially if I outline my eyes all the way around with black eyeliner, the blue is enhanced. In brighter light I think it helps them look blue because the pupils are small, which I think @LuckyGuy mentioned. Also, @snowberry is right that mood can affect the pupils also.

Once in a blue moon :) someone looks at me and asks if my eyes are green or some other color, and I simply dismiss it as an eyesight problem. Their eyesight problem.