What is a high power lens designed to have its prescription power only in the center portion?

A high power lens designed to have its prescription power only in the center portion is known as a lenticular lens. These lenses are specifically constructed with a thick, convex center that allows for a strong prescription to be concentrated in a limited area, which is particularly beneficial for individuals with high degrees of refractive error.

Lenticular lenses differ from regular lenses in that they incorporate a smaller optical zone for the prescription, surrounded by a much thinner non-optical periphery. This design minimizes the lens weight and distortion experienced in conventional high power lenses. The center portion of the lenticular lens provides the necessary corrective power, while the edges are less bulky, improving both comfort and aesthetics for the wearer.

In contrast, bifocal lenses contain two distinct optical powers, usually for distance and near vision, while trifocal lenses add a third intermediate segment. Progressive lenses provide a smooth transition between multiple optical powers for distance, intermediate, and near vision without the visible lines found in bifocal and trifocal lenses. Neither bifocal, trifocal, nor progressive lenses focus prescription power solely in the center, which is a defining characteristic of lenticular lenses.