The principle of glasses

The principle of this kind of lens is to change the focus of light through the lens and help improve vision.

Myopic glasses use concave lenses to disperse light and image distant objects on the retina. Hyperopia glasses use convex lenses to focus light, so that near objects can be imaged on the retina.

Astigmatism glasses use cylindrical lenses to adjust the direction of light and solve the problem that light cannot focus. Reading glasses also use convex lenses to enhance focus and help the elderly to see nearby objects clearly.