I worked on Paint Shop Pro a long time ago, when they first added red eye correction. It did it not by manipulating the image, but by painting an artificial ey

I worked on Paint Shop Pro a long time ago, when they first added red eye correction. It did it not by manipulating the image, but by painting an artificial eye over the original. The dialog was hellishly complex since you had to specify not only how the new eye should look but how to make it match the original. But it delivered impressive results. Last I saw, it was scheduled to be replaced with something simpler and more traditional in the next version.