Refractive Power

The refractive power is a physical quantity. It is closely related to the focal length. When parallel beams from a very distant object fall through a converging lens, these beams meet behind the lens and produce an inverted image of the object. The distance between the lens and this focal plane is the focal length (in meters). The refractive power is then the reciprocal of the focal length and is given in dioptres (dpt) (1 dpt = 1/m). A focal length of 2.5 cm corresponds to 40 dpt. The total crushing power consists of the crushing power of the four media: The cornea has the greatest refractive power with approx. 40 dpt, the lens has 15-30 dioptres depending on the degree of curvature. Since the refractive power of aqueous humor and vitreous humour is negligible, a total refractive power of approx. 60 dpt is calculated for the eye when looking into the distance.