I belong to a traditional only site and this topic has come up a few times. Not only is it ok to move the sight forward it is even considered "PC" because there are many examples of this being done. People back then bought a rifle for life and they had no choice but to move the sights when they could not see then anymore. People have found rifles with more than two notches filed into the barrel as the sights were moved forward for better sight picture.

I would say go for it if it helps and you really like your rifle. You may ask you eye doctor if he can help you fint the right focal point.