In terms of thickness, how does a concave lens differ from a convex lens?

A concave lens is characterized by its curvature, which is shaped inward or "caved in." This specific design results in the lens being thinner at its edges compared to the center. As light passes through a concave lens, it diverges, creating a virtual focal point from which the light seems to emanate.

In contrast, a convex lens bulges outward and is thicker at the center, which allows it to converge light rays to a focal point on the opposite side. The differential in thickness between concave and convex lenses is largely what enables their distinct optical behaviors.

Thus, saying that a concave lens is thinner at the edges accurately describes this fundamental property, reinforcing its role in optical applications such as in eyeglasses for nearsightedness, where the lens aids in diverging light to improve vision. This distinction is crucial in optics, as it affects how lenses interact with light and thus their practical applications in various optical devices.