An eyelid parameters auto-measuring method based on 3D scanning

Background: Various distance as well as angle measurements of facial structures are evidence of proper ocular plastic and eyelid disease surgery plans. Surgeons nowadays make decisions based on so called experience, which is non-quantitative, resulting in low dissemination efficiency. Purpose: To establish a method for eyelid parameter automatic quantification without mega data labeling and training, facilitating the popularization of eyelid related surgery design. Methods: An automatic measurement of eyelid parameters is described. It is composed of obtaining of absolute distance between left inner canthus and right inner canthus by 3D models of human faces, calculation of 22 eyelid parameters based on face landmarks, converting 18 distance-related eyelid parameters' values which correspond to relative distance to real distance. Results: An auto-measurement of 80 normal patients and 60 TAO patients is conducted. By comparison to manual-measurement, we achieved relative errors less than 10% and 13% for regular eyes and diseased eyes. Conclusions: Eyelid related characteristics are quantified in an easy, portable and precise way. Based on which, series of approaches in quantitative evaluation, operation selection and extensive dissemination may develop in the fields of eyelid disease and ocular plastics.