Presbyopia, or presbyopia, is a normal physiological phenomenon. It is neither a pathological state nor a refractive error. It is a visual problem that must occur after people enter middle-aged and old age, and it is one of the signs that the body is beginning to age.

High-quality sunglasses can completely eliminate ultraviolet radiation and reduce damage to the cornea and retina caused by ultraviolet rays. When the eye receives too much light, it naturally contracts the iris.

A convex lens is thicker in the center and thinner at the edges. For patients with myopia, a convex lens can cause the light to diverge outward after passing through the lens, causing the focus of the light entering the eye to move backward, thereby focusing on nearby objects.

Progressive lenses, also known as progressive lenses, are special lenses that correct refractive errors. On the surface, it is no different from ordinary single vision lenses, but in reality it is completely different from single vision lenses.