A cascade needs to be generated using a facial database that can detect when the user's eyes are closed. This is needed in order for a user to click the mouse cursor on an item on the screen. The haarcascade_eye.xml provided by OpenCV has previously been used.

Some suggested facial databases have been recommended previously:

http://www.face-rec.org/databases/
http://www.ecse.rpi.edu/~cvrl/database/other_Face_Databases.htm
http://web.mit.edu/emeyers/www/face_databases.html
http://www.nist.gov/itl/iad/ig/colorferet.cfm