There are a lot of things that can make or break a mod, but for the most part, it is the compatibility that is the most important. If the mod works with the game, then it is good and you can use it, but if it does not work, then you have to look for another mod that does work. This is why it is important to find out which version of the game you are working on.

Fortunately, this extension works well with Dragon Age: Origins. This mod allows you to change the eye color of your character with better tints.

If you are playing on the PC version of the game, then you can download this extension and install it in the folder: 
\Program Files\Dragon Age\packages\core\override