Which type of lens is thicker at the center than at the edges?

A lens that is thicker at the center than at the edges is described as a convex lens. Convex lenses are shaped such that they converge light rays that are incident on them, causing the rays to meet at a focal point. This characteristic is pivotal in various optical applications, such as magnifying glasses and converging lenses in eyeglasses.

Convex lenses have positive focal lengths and are commonly used to correct hyperopia (farsightedness). When light passes through a convex lens, it bends towards the central axis, which leads to the creation of a focused image. This property is harnessed in many optical instruments to enhance clarity and detail.

In contrast, concave lenses are thinner at the center and thicker at the edges, causing light rays to diverge. Plano lenses are flat and do not have any curvature to converge or diverge light, while cylindrical lenses have a specific curvature that allows them to focus light in one direction but not the other. Therefore, the characteristics of a convex lens distinctly align with the description provided in the question.