The vertical distance between the upper lid margin and the superior limbus of the cornea defines the extent to which the upper portion of the eye is visible. An individual with a measurement considered to be within normal limits typically displays a certain amount of the iris above the pupil. Deviations from this range, whether excessive or insufficient, can impact both functional and aesthetic aspects of the face.
Appropriate visibility of the superior sclera is crucial for optimal vision and facial expression. Too much or too little scleral show can contribute to dry eye symptoms, corneal irritation, and altered perceived emotional states. Historically, assessments have relied on subjective evaluations; however, modern techniques increasingly utilize precise, objective measurements to quantify this parameter.
