My 16yr old DS was diagnosed with colour deficiency when he was 4. He is unable to see certain shades of green and is missing most of the green cones in his eyes.
It is really interesting as he sees the new model green VW beetles as being orange, even though they're clearly green to those of us without colour deficiency.

He has adjusted over the years to this and I have noticed as he has somewhat improved with certain colours. You can google the colour tests to do at home which can give an indication. I think 2 is too young to test properly though.