unit force lenses?, In optics, lens power is measured using the unit “diopter” (abbreviated as D). Diopter is a measure of the refractive power of a lens. It indicates how much a lens can bend light rays.
With lenses, a distinction is made between converging and diverging lenses. Converging lenses are convex lenses that direct light rays towards each other while diverging lenses direct light rays away from each other.
For converging lenses, the diopter is positive. The higher the diopter, the stronger the lens and the more it can direct light rays towards each other. For example, a lens with a power of +2.00 D is stronger than a lens with +1.00 D.
For diverging lenses, the diopter is negative. The higher the absolute value of the diopter (the number without the plus sign), the stronger the lens and the more it can deflect light rays from each other. For example, a lens with -2.00 D power is stronger than a lens with -1.00 D.
Determining the correct power of a lens is very important for people who need glasses or contact lenses to correct their vision. Optometrists and ophthalmologists perform eye exams to determine the correct lens power so patients can see clearly and sharply.