Originally Posted by Riot Ambassador
Colorblind mode is one of the many improvements we are actively working on. While we don’t have definitive information yet regarding its release, it is a very high priority for us here at Riot Games. We will have more updates as we get closer to a concrete release date.
Currently using a user created Color Blind plugin, however it has it's limitation. I'm not so sure why it is so hard to implement, it's been asked for multiple times and not just this year.
There are some problems with the user created one, like health bars randomly protruding from the champion, and unable to tell shield, etc. Being a programmer myself, adding a color blind mode seem trivial and I'm rather disappointed that it hasn't been added.