Eyelid contour measurement

Purpose. To use image processing routines to quantify the upper and lower eyelid contours. Methods. A CCD camera with 100 mm 1:34 zoom lenses and a Power Mackintosh equipped with a Scion frame-grabber were used to acquire palpebral fissure images of 30 normal subjects. The subjects were instructed to look to the camera that was aligned with the right or the left eye at 1 meter of distance. A chin resl was used to stabilize the subjects' head. The images were processed by the NIH IMAGE 1.55 software A set of points delineating the upper and lower eyelid contours was selected for curve fitting. The center of the pupil was also recorded. Results. The upper eyelid contour is well adjusted by a second degree polynomial funclion (mean-0.00339lx: + 2.03891x -4.72945). The lower eyelid contour is more complex and weil adjusted by a third degree polynomial function (mean= -0.000522x' +0.073212x: -2.898682x +50.883146). For most subjects, the highest point of the upper eyelid was medial to the pupil center (mean = 0.54 mm) The lowest point of the inferior eyelid was constantly temporal to the pupil center (mean -1.34mm). Conclusions. Software image processing can provide accurate information on eyelid contour and other palpebral fissures features. This type of information can be clinically useful for recording and characterizing eyelid changes provoked by diseases.