1. The length of eyelid fissure in adult eyes is 30-40 mm, which is generally about one fifth of its width.

2. The distance between the inner canthus of both eyes is 30-60mm. The vertical diameter of ptosis is10-12.5 mm. ..

3. The eyelid angle of inner canthus is 48-55, that of outer canthus is 60-70, and the included angle of the horizontal line connecting inner canthus and outer canthus is about10.

4. When the eyes are looking straight, the upper eyelid covers the cornea for 2mm, and the edge of the lower eyelid contacts the edge of the lower cornea.