On a normal frame with 10 to 12 degrees of pantoscopic tilt, where should the optical center be located?

In a normal frame with a pantoscopic tilt of 10 to 12 degrees, the optical center of the lenses should ideally be positioned slightly below the pupil. This positioning is crucial for ensuring that the wearer experiences optimal visual comfort and clarity. The correct choice of 5mm below the pupil reflects this alignment.

When lenses are tilted forward (which occurs with pantoscopic tilt), the line of sight is altered. By placing the optical center a few millimeters below the pupil, it compensates for the angle of gaze and ensures that the individual's line of sight hits the optical center of the lens when looking straight ahead. If the optical center were too high or improperly aligned, it could lead to visual distortions or discomfort, particularly when the wearer is trying to focus on objects directly in front of them.

This specific adjustment plays a key role in frames designed for everyday activities, where a balance between aesthetic appearance and functional vision is desired. The choice to place the optical center at 5mm below the pupil effectively enhances the wearer's ability to see clearly and comfortably at various distances.