Which characteristic of a lens determines its focusing power?

The curvature of a lens is a key factor that determines its focusing power. This characteristic relates to the shape of the lens surfaces, which influences how light rays are refracted as they pass through the lens. A lens with a more pronounced curvature will bend light rays more sharply, resulting in a stronger focusing power. Conversely, a flatter lens will have less ability to converge or diverge light, resulting in weaker focusing capabilities.

Additionally, the curvature determines the focal length of the lens—the distance from the lens to the focal point where light rays converge. A shorter focal length, associated with a steeper curve, equates to a stronger lens; this is crucial in various optical applications, including correcting vision deficiencies. Thus, understanding the relationship between curvature and focusing power is essential in both refractive surgery and the design of corrective eyewear.