As we can see from the problematic results described previously, the function we have written should be used very cautiously if we want to have a good output. A way to improve it would be to take into consideration additional properties of eyes, such as their radial symmetry. Since our eyes are circular, the red region should also appear circular. This can be detected using an image presented in Chapter 3, Morphological Operations and Object Analysis, imfindcircles. Let's see how.