Computerised 3D evaluation of the functional eyelid deficit in facial palsy.

Facial palsy is often characterised by a severe dysfunction of the eyelids, leading to corneal ulceration and even blindness. A precise evaluation of the exposed ocular surface is very important in order to estimate the risks of these ocular symptoms. In the literature, most authors use a comparison between the heights of lagophthalmus and corneal exposure in the pre- and postoperative situations to evaluate the surgical correction of the eyelids in facial paralysis. The heights are not representative of the real exposed surfaces. We propose another method to evaluate these surfaces, using a computer-assisted design (CAD) software analysing standardised photographs and giving a precise assessment of the surface of the eye not covered by the eyelids. The exposed surface is more representative of the risks of ocular symptoms than the height. Our goal in this study was to improve the quality of the measurements, which allows to get a better estimation of the clinical situation and provides a tool that permits comparison of results between different surgical approaches.