  Operating a GUI through eyeball is a complex mechanism and not used as often
as mouse or trackball. But there are situations where eye-mouse devices can
play a tremendous role especially where the hands of the user are not available
or busy to perform other activities. The difficulties of implementing an
eye-cursor control system are many. The article illustrates some inventions on
eye-cursor control system, which attempt to eliminate the difficulties of the
prior art mechanisms.
