If a person wanting bifocals is stooped, you should which seg height adjustment?

• A. Lower
• B. Maintain
• C. Raise
• D. Adjust by 0.5 mm

Answer: (D)

When fitting bifocals, the vertical position of the reading segment must match the wearer’s typical line of sight during the reading posture. Someone who tends to stoop looks downward more, so the eye’s viewing path through the near portion shifts lower in the lens. To keep the reading segment aligned with the pupil in that posture, you make a small downward adjustment of the segment height. A precise, modest shift of about half a millimeter is the practical correction that places the near portion where it will be seen most naturally when reading while stooped, without creating new alignment issues for other viewing angles. Larger changes (lower or raise by more substantial amounts) can misalign the segment for normal posture or force uncomfortable head positioning. Maintaining the current height would not compensate for the altered gaze, leading to less comfortable vision through the near portion.