What characteristic is true regarding semi-finished lenses?

Semi-finished lenses are designed to have certain features that allow them to be customized for specific prescriptions after their initial production. The characteristic that is true for semi-finished lenses is that only the front surface is ground or molded to a specific curvature. This permits optical laboratories to easily adjust the lens by surface modification to meet individual prescriptions.

The design of semi-finished lenses typically involves leaving the back surface in a more basic or neutral state, which enables further alterations without compromising the optical quality. The practice of grinding only the front surface reduces manufacturing complexity and cost while allowing for versatility in lens fitting.

In regards to other characteristics: While both surfaces of a finished lens would typically be polished and shaped to enhance optical performance, semi-finished lenses prioritize the front curvature to maintain a balance between production efficiency and the potential for customization. Additionally, semi-finished lenses are not restricted to being made from glass only; they can also be produced using various types of plastic materials, making them suitable for a wide range of applications. Thus, the correct answer about semi-finished lenses accurately reflects the typical production process.