I recently wrote a simple Color-Blind Utility for NGUI: Next-Gen UI, the add-on allows you to assign alternate colors and sprites from an atlas to UISprites, as well as colors and fonts to UILabels (including those targeted by a UIButton’s color tweening). This add-on also includes a color-blind simulation post-processing effect to be used for testing purposes (Requires Unity Pro License). I designed the add-on in such a way that it should integrate fairly seamlessly into the pre-existing NGUI toolset and be easily modifiable from an API level, making it easy to integrate into a game’s settings menu.

Asset Store Link: https://www.assetstore.unity3d.com/en/#!/content/17418