This distance between the MRP to the top of the bifocal segment is known as ________________.

This distance between the MRP to the top of the bifocal segment is known as ________________.

• A. Seg drop
• B. Bifocal height
• C. Segment offset
• D. Top segment

Answer: (A)

Seg drop is the vertical distance from the monocular reference point on the lens (MRP) to the top edge of the bifocal segment. The MRP serves as the reference point used to align the lens’s optical geometry in the frame, so this measurement tells you how far down the bifocal reading portion sits from that reference. A larger seg drop moves the segment lower in the wearer's поле of view, making the reading area appear farther down, while a smaller seg drop brings the top of the segment higher. This specific distance is distinct from bifocal height, which is a more general vertical sizing of the segment, and from horizontal adjustments like segment offset.

Seg drop is the vertical distance from the monocular reference point on the lens (MRP) to the top edge of the bifocal segment. The MRP serves as the reference point used to align the lens’s optical geometry in the frame, so this measurement tells you how far down the bifocal reading portion sits from that reference. A larger seg drop moves the segment lower in the wearer's поле of view, making the reading area appear farther down, while a smaller seg drop brings the top of the segment higher. This specific distance is distinct from bifocal height, which is a more general vertical sizing of the segment, and from horizontal adjustments like segment offset.