Refraktsioonivõimega

Refraktsioonivõimega, often translated as refractive power or dioptric power, is a concept used in optics, particularly in the context of lenses. It quantifies how strongly a lens or optical system converges or diverges light. The unit of refractive power is the diopter (D).

A lens with a positive refractive power converges parallel rays of light to a focal point, meaning it has a converging effect. Conversely, a lens with a negative refractive power diverges parallel rays of light, making them appear to originate from a focal point on the same side of the lens. The higher the absolute value of the refractive power, the stronger the lens's ability to bend light.

The refractive power of a lens is inversely proportional to its focal length. Specifically, refractive power (P) in diopters is equal to 1 divided by the focal length (f) in meters: P = 1/f. For example, a lens with a focal length of 0.5 meters has a refractive power of +2.00 D, and a lens with a focal length of -0.25 meters has a refractive power of -4.00 D.

This concept is fundamental in ophthalmology for prescribing corrective lenses for vision impairments. Eyeglasses and contact lenses are designed with specific refractive powers to correct conditions like myopia (nearsightedness) and hyperopia (farsightedness) by adjusting the focusing of light onto the retina.