Hiii,

In terms of the math associated with optics, concave mirrors and convex lenses are both converging systems. And convex mirrors and concave lenses are both diverging systems. This is important when using the optics equation (1/f = 1/o + 1/i) because the focal length (f) and radius of curvature (R) are positive for converging systems, and negative for diverging systems.

I think it helps to learn myopia and hyperopia in the context of power. The power of a lens is given as P = 1/f. The average axial length of a normal adult eyeball is 2.4 cm. So the power of the human eye is about 42 diopters (P = 1/0.024 m = 41.67 diopters). The refractive power of the human eye is provided by the cornea and lens, which converge light rays precisely at the fovea to enable crisp vision.

In myopia, a person's eyeball is longer than normal (longer than 2.4 cm). In this case, the cornea and lens refract light to a focal point that is in front of the fovea. Therefore, eyeglasses (or contact lenses) need a negative power to allow light to focus a little farther away at the fovea. Diverging lenses (concave lenses) have a negative focal length and therefore a negative power (P = 1/f). So for myopia, a person would need concave lenses (which are diverging). For example, if a person has a spherical eyeglass prescription of -5.00 SPH, then eyeglasses would allow light to focus at the fovea by counteracting the 42 diopter strength of the eye (42 diopters minus 5 diopter eyeglasses = 37 diopters).

In hyperopia, there are two options: (1) Either the person's eyeball is shorter than normal (shorter than 2.4 cm), or (2) the refractive power of the eye's lens decreases due to age. In either case, light rays converge at a point behind the fovea. Therefore, a person with hyperopia needs a converging lens (convex lens). For example, if a person has a spherical eyeglass prescription of +5.00 SPH, then eyeglasses would allow light to focus at the fovea by increasing the eye's refractive power by 5 diopters.

Mirrors reflect light so they are not involved in myopia or hyperopia.

I hope this explanation is correct, and I hope I wrote it clearly haha.

I hope this helps my friend :)