Does the colour (wavelength) of the light change, when it enters an optically denser medium? Light passes through the ocular fluid of our eye, after passing through the lens of the eye, before striking our cones. Irrespective of what medium it passes through, we will always perceive the same color? Thus, does it matter, what medium it passes through?
 A: The wavelength does change, but the color does not.
Because color is more properly linked to frequency and frequency remains the same. Yes, I know, many sources link it to wavelength but if they want to do that they should be linking it to vacuum wavelength.
Here's why you should consider color as a function of frequency:


*

*You eye responds to photons according to their energy because the complex molecules that are visual pigments get excited through certain ranges in energy.

*Quantum mechanically the energy is linked to frequency by
$$ E = h f \;,$$
rather than to wavelength (which affects momentum).
A: I could be wrong here - but I once had a physics book about microscopes & optical techniques, that said that some polarization occurs in most crystalline media as there are many internal "faces", which changes the energy & therefore the color, when some energy is shifted towards the polarized plane direction, but the effect we see is subtle, - I can't find the reference right now. Hope this helps, I'll be back if I find my source!
