The knowledge about the exact position of the eyelid in a videokeratoscopic image is useful in many ways, for example:

• As a preprocessing step for enhancing the videokeratoscopic image for a more accurate corneal topography estimation, especially for people with a small eyelid aperture.
• For studying the impact of the force caused by the eyelids on the corneal topography.

The detection of the eyelid can be divided into two steps:

• Detection of the edge points of the eyelid by using image segmentation techniques.
• Fitting of a parametric model to the detected edge points.