How can I localize the upper and lower eyelids after obtaining the iris Boundaries?

Hi After using this : http://www.mathworks.com/matlabcentral/fileexchange/15652-iris-segmentation-using-daugman-s-integrodifferential-operator.

I need to localise the upper and lower eyelids in MATlab and I was wondering if there was a way to find arcs like these then remove them from the Iris Boundaries that have been found

Here is the eye Image:

[Penta]

Hi Yannick, I'm working in the same area, it'd be really helpful for me if you could share your code for Iris recognition.