Red eye starting to darken

[pyrotarukia]

Hey guys!

I've never had a "red eyed" gerbil before as personally I've never been fond of their colourings however with my two current boys I have, the one that my partner picked has/had red tinting in his eyes that when he is directly under the light it looks red and if he's in the shade it looks darker brown but not black like my other boy however I recently went on a trip back to the UK to visit family and friends (my partner stayed behind in Norway to look after the boys and he had work) and when I came home 2 days ago I've noticed that even under lighting Loki's eyes look a brown colour a darker duller intensity of the red it used to be.

Is it common or even possible for red tinted eyes to darken over time?

[betty]

What colour is your gerbil?

A lot of colourpoint gerbils can have a reddish tint to the eyes under certain light, but their eyes basically look brown/black most of the time.

Do you have a good picture of him?

[pyrotarukia]

Loki is the lighter of the 2 gerbils (the one on the right) of my signature his eyes are dark there because they were pretty pinky so my camera auto "red eye corrected" lol but usually they are quite reddish as I said in the light.
I say reddish because it's not the extreme red I have seen in some white rodents. I'm just wondering if it's possible for the red to fade over time.. I'd have thought not as like people eye colours don't really change but in some rare cases they can I have taken Loki out and held him under the lights and his eyes still have a red tint but it seems a lot darker then it did before.
They are both young gerbils and still growing so I don't know if that can have any effects on them.

He's also not very photogenic xD but these are pictures from before I changed their tank so just over a month ago I think:




We just took him to the exact same spot as his old cage for these pictures taken 5 mins ago:




His eyes only seem to get to this darker brown now. 

Edit:
I'd also like to add that all 4 of these photos were taken on my iPhone so no red eye correction and no different shutter settings etc, under the same lighting conditions and in pretty much the same place.