For example, if you shrink a photo to 320 x 240 pixels, perform a histogram equalization on it, use the LBP frontal face detector to get a face, then extract the left-eye-region and right-eye-region from the face using the haarcascade_mcs_lefteye.xml values, then perform a histogram equalization on each eye region. Then if you the haarcascade_mcs_lefteye.xml detector on the left eye (which is actually on the top-right side of your image) and use the haarcascade_mcs_ righteye.xml detector on the right eye (the top-left part of your image), each eye detector should work in roughly 90 percent of photos with LBP-detected frontal faces. So if you want both eyes detected then it should work in roughly 80 percent of photos with LBP-detected frontal faces.