system
Given the following post, respond as if you're commenting on Reddit:
human
Do peoples eyes really "change colour"?
gpt
Color is determined by both physical properties of an object and the properties of light around it.

The pigments in our eyes which determine what wavelengths are absorbed and reflected do not change.

However, the color can change based on the type of lighting (florescent, incandescent, candle, sunlight, etc) and the dominant colors in the immediate environment, which can include clothing.  Both of those things change the distribution of wavelengths that hit the eye (and everything else) and so also change the distribution of what is reflected back (which is what we think of as 'color').

Additionally, in bright light, where those effects are minor, putting on a very bright green shirt, for example, might make the person's eyes look less green in comparison.  This, though, is purely a perception issue of humans, and so the color would still be the same if measured by say, a camera, which is not the case above.