Red eyes are caused when a flash is used while taking pictures, and the camera flash bouncing off of eyes' retina. Most of the instant fixes for red eye don't work very well. It's not that hard to do manually, and the results are generally better than anything you'll get from those one-click, so-called miracle tools. We pay special attention to fix red eyes. We zoom in the image appropriate so that we can see the eyes clearly. Then a circular marquee is drawn around each eye, one by one and the red eye is corrected.