How many curves are present in a tricurve GP lens?

How many curves are present in a tricurve GP lens?

• A. Three curves
• B. Two curves
• C. Four curves
• D. Five curves

Answer: (A)

The main idea here is how a tricurve GP lens is structured on the back surface. A tricurve design uses three distinct curves on the lens’s back surface: a base curve near the center, an intermediate curve in the mid-zone, and a peripheral curve toward the edge. These three segments create a stepped back surface that matches the cornea’s shape from center to periphery, promoting a stable, well-centered fit and good tear exchange. The front surface carries the optical power and is usually a single curve, but the designation “tricurve” refers to the back-surface composition. So, there are three curves in a tricurve GP lens.

The main idea here is how a tricurve GP lens is structured on the back surface. A tricurve design uses three distinct curves on the lens’s back surface: a base curve near the center, an intermediate curve in the mid-zone, and a peripheral curve toward the edge. These three segments create a stepped back surface that matches the cornea’s shape from center to periphery, promoting a stable, well-centered fit and good tear exchange. The front surface carries the optical power and is usually a single curve, but the designation “tricurve” refers to the back-surface composition. So, there are three curves in a tricurve GP lens.