When measuring segment heights, it is critical to take into consideration the following:

• A. All of the above
• B. Frame height
• C. Patient age
• D. Lens material

Answer: (A)

When measuring segment heights, aim to align the bottom of the near portion with the wearer's line of sight at typical reading angles, so vision through the near zone is comfortable and natural. Frame height determines how much vertical space is available in the lens for the segment; a frame with limited vertical room can push the segment too low or cause it to be clipped, while a frame with more height can accommodate a taller segment. Patient age matters because reading needs and working distances shift with age, affecting where the near zone should be placed to be useful without causing neck or head strain. Lens material influences the practical geometry of the lens—thickness, edge shape, and how the segment sits within the frame can change the effective height you measure and fit. Because each factor can alter the ideal position of the segment, it’s important to consider all of them to ensure proper function and comfort.