Saiki's eye color

So I saw this old blog post by CupcakeV talking about why Saiki has pink hair. Now, Saiki has mentioned that he was the only one in Japan born without black or brown hair at the time, so he caused the change. My question is, is it the same with his eyes? Purple isn't a natural eye color (well, it kinda is, but not dark purple), and Japanese people don't tend to have blue, orange, green, etc. eyes. Did Saiki also cause this change, or were weird eye colors always common in his world?