What term describes the offset from the geometric center to the MRP?

What term describes the offset from the geometric center to the MRP?

• A. Inset
• B. Seg Inset
• C. Total Inset
• D. Near PD

Answer: (A)

Inset describes the horizontal shift from the geometric center of the lens to the monocular reference point used for centration (MRP). When the frame is fitted, the MRP is the reference point that the lens is aligned to, and the distance from the lens center to that point is the inset. This ensures the wearer’s eye looks through the intended part of the lens. Seg inset would apply to a segmented bifocal portion, total inset would combine frame and segment shifts, and near PD is a separate measurement for near-work alignment. So the offset from the geometric center to the MRP is called the inset.

Inset describes the horizontal shift from the geometric center of the lens to the monocular reference point used for centration (MRP). When the frame is fitted, the MRP is the reference point that the lens is aligned to, and the distance from the lens center to that point is the inset. This ensures the wearer’s eye looks through the intended part of the lens. Seg inset would apply to a segmented bifocal portion, total inset would combine frame and segment shifts, and near PD is a separate measurement for near-work alignment. So the offset from the geometric center to the MRP is called the inset.