Purpose: To quantify the relation between eye and eyelids placement in different positions during downgaze and upgaze in healthy subjects.
Methods: The position of the eye and eyelids of 10 healthy individuals was quantified by palpebral fissure image processing with NIH Image software. Upper and lower mid-pupil margin distance was measured in 7 positions: -30, -20, -10, 0, +10, +20 and +30 degrees (positive signs correspond to upgaze and negative signs to downgaze) along vertical meridian.
Results: The upper mid-pupil margin distance decreases in upgaze and even more in downgaze. The lower mid-pupil margin distance increases in upgaze and decreases in downgaze. About the palpebral fissure height, it gets larger in upgaze until 20 degrees and smaller in downgaze.
Conclusion: Our data showed that the interpalpebral fissure height varies with vertical meridian gaze amplitude and that considerations about mid-pupil margin distance must consider the amount of upgaze or downgaze.