When fitting a progressive addition lens (PAL) for a child, where should the fitting cross height be?

For fitting progressive addition lenses (PALs) in children, the fitting cross height is typically set at 4 mm above the pupil center. This specific positioning is important because it allows for optimal vision through the various zones of the lens, particularly the reading add zone located at the bottom of the lens.

When children look down to read, their eyes naturally align with the lower part of the lens if the fitting cross is properly positioned. By placing the fitting cross higher than the pupil center, it ensures that when they look down, their gaze falls directly into the reading area of the lens, facilitating clear near vision while still allowing for adequate distance vision through the upper part of the lens when they look up.

This fitting height takes into account the head and eye movements common in children and promotes comfort and functionality, making it easier for them to adapt to wearing progressive lenses. If the fitting cross were positioned too low or at the pupil center, it could interfere with their ability to see clearly in both near and distance vision, leading to potential issues with usability and adaptation.