What shape describes concave lenses?

Concave lenses are characterized by their inward curvature. This shape causes light rays that pass through the lens to diverge, or spread apart, rather than converge. The inward curve is essential in the design of these lenses, as it allows them to focus images more effectively for specific applications, such as correcting vision for nearsightedness. By bending light rays outward, concave lenses create virtual images that appear closer to the observer, which is especially useful in various optical devices like glasses and cameras. The unique shape of concave lenses distinguishes them from other types of lenses, which either curve outward or have flat surfaces.