Unit of measure of the refractive power of the eye
a unit of measurement based on the reciprocal of the focal length of the lens expressed in metres.
(or diopter). Unit of vergence, giving the refracting power of a lens as the reciprocal of its focal length, in metres. Minus indicates diverging and plus indicates converging.
A measurement of the degree to which light converges or diverges; also a measurement of lens refractive power. EpiLASIK EpiLASIK is an innovative new procedure designed to restore natural vision with the help of an epikeratome. The surgeon uses an epikeratome, a separator that creates an epithelial sheet, to make a thin flap in the epithelium. The Wavefront based excimer laser beam is then applied under the epithelial flap to successfully correct refractive errors and restore clear vision.
Refractive power of a lens. A lens having a focal length of one metre is said to have a power of one dioptre, a lens of 20 centimetre focal length has a power of +5 dioptres, one of 5 metres focal length has a power of -5 dioptres.
A dioptre, or diopter, is a non-SI unit of measurement of the optical power of a lens or curved mirror, which is equal to the reciprocal of the focal length measured in metres (that is, 1/metres). For example, a 3 dioptre lens brings parallel rays of light to focus at 1/3 metre. The same unit is also sometimes used for other reciprocals of distance, particularly radii of curvature and the vergence of optical beams.
