Definitions for

**"Diopter"****Related Terms:**Dioptre, Multifocal, Power, Bifocals, Aspherical lens, Aspheric, Multifocal lens, Concave lens, Convex lens, Progressive lenses, Magnifying glass, Aspheric lens, Diopter adjustment, Spherical aberration, Diopters, Lens, Aspherical, Bifocal lens, Bifocal lenses, Trifocal lenses, Trifocal lens, Converging lens, Accommodation, Normal lens, Relative aperture, Compound lens, Exit pupil, Bifocal, Trifocal, Refracting telescope, F-number, Progressive lens, Telecentric lens, Plano, Magnification, Long lens, Aberration, Objective lens, Fish-eye lens, Hyperopia, Crystalline lens, Mirror lens, Hypermetropia, Fresnel lens, Telephoto lens, Eyepiece, Focal length, Barlow lens, Teleconverter, Telephoto

An optical instrument, invented by Hipparchus, for taking altitudes, leveling, etc.

Unit for measuring a lens' refractive power. In photography, the term is used with close-up lenses and corrections to the viewfinder to adjust it to the user's eyesight.

(D) (di-AHP-tur): Unit designating the refractive power of a lens.

a unit of measure of the refractive power of a lens or of an eye, where the dioptric power is the inverse (reciprocal) of the focal length of the lens or of the eye's optical system in meters; a +1.00 D convex lens focuses light, from an infinite source, 1 ÷ 1.00 D = 1 meter away from the lens (and corrects an eye which is 1.00 D hyperopic); a +2.00 D lens focuses infinite light 1 ÷ 2.00 D = 1/2 meter away (and corrects an eye which is 2.00 D hyperopic); a +0.25 D lens focuses infinite light 1 ÷ 0.25 D = 4 meters away (and corrects an eye which is 0.25 D hyperopic); etc.

It identifies the power of a lens and it expresses the reciprocal of the lens focal length in meters. A negative DIOPTER number represents a diverging lens and a positive one represents a converging lens. For example, a close-up (positive) lens with a focal length of 50 cm (1/2 meter) would be labeled a +2 lens.

Optical term for the power of a lens. Photographically, it is typically used to indicate the magnification and focal length of close-up lenses.

A unit of measure of the refractive power of a lens, equal to the power of a lens with focal distance of one meter.

A unit of measurement used by eye doctors and opticians to communicate the degree of refractive error with respect to nearsightedness, farsightedness, and astigmatism.

The unit of measure of the power of a lens.

A measurement of refractive power of a lens equal to the reciprocal of the focal length in meters. A lens with 20 centimeter focal length has power of five diopters, while one with a 2 meter focal length has a power of 0.5 diopter.

unit of measurement that describes the refractive (light-bending) power of a lens and is used in prescriptions. A negative value indicates a correction for nearsightedness ( myopia), while a positive value indicates a correction for farsightedness ( hyperopia).

Close-up lenses (which screw into the front of an existing lens and act like a reading glass) are often marked in "diopters" (2.5 diopter close-up lens) The diopter value of a lens is calculated by taking the reciprocal of the focal length expressed in meters. Each diopter is the number of times the focal length of the lens will divide into one meter

Unit of measurement used to indicate how much light rays are refracted or bent by a lens.

Unit of measurement of refractive power of lenses.

a metric measurement of the lens power

a supplementary lens which looks like a filter and screws on the front of the prime lens to allow it to focus closer

a unit of measurement related to the focal length of an optical system including the human eye

a unit of measurement representing lens power

a unit of measurement that determines your prescription

a unit of measurement that helps determine how much a lens should be altered to bend or refract light rays to achieve correct focus

a unit of measurement that is simply the inverse of the focal distance of the lens as measured in meters

a unit of measurment based on how much light rays will bend as they pass through the lens

A measure of how strong your lenses are, usually denoted by a number and "D" e.g. 3.00D.

A unit of measurement for myopia, hyperopia and astigmatism that usually falls within a scale of +14 to -14. A positive number indicates hyperopia and a negative number indicates myopia.

a unit of measurement for optical lenses. The number of diopters indicates the quantitative change in the distance between the lens and the focal point of light rays entering the lens. A positive diopter value describes a convex lens, while a negative value describes a concave lens. This differentiation describes the focal point of light entering a convex lens as being beyond the lens, while the focal point of light entering a concave lens as being in front of the lens. See convex lens, concave lens.

An adjustment on the eyepiece of a camera that allows you to correct the focus of the eyepiece to match your vision.

a unit of measurement — abbreviated as “D” on medical charts. It measures the degree to which light converges or diverges within the eye or through a lens, such as an eyeglass lens or contact lens.

A full measure of the optical lens, done for those needing glasses.

A unit which measures the amount of a refractive error. Glasses and contacts are prescribed in diopters.

metric unit used to denote the refractive error of the eye or lens

the measure of lens strength. =1/(focal length in metres)

A unit expressing the refractive power of an optical system/component as the reciprocal of the focal length in meters.

An optical unit of measure of the refractive power of a lens, the reciprocal of its focal length.

unit to designate the refractive power of lens.

Unit used to measure the amount of refractive error (nearsightedness, farsightedness and astigmatism) of an eye. Intacs are intended for people with a refraction between -1.0 and -3.0 diopters.

is the measurement of refractive error. When used in excimer refractive surgery, diopter is a measurement of the refractive power of the eye. In LASIK and other refractive procedures, a negative diopter value signifies an eye with myopia and positive diopter value signifies an eye with hyperopia.

A unit of focusing power of a lens. A two diopter lens is twice as strong as a one diopter lens. While a 1 diopter lens will focus light at one meter (39.3inches) a two diopter lens will focus light at half a meter (19.7 inches). This is because the two diopter lens will bend or focus a beam of light more than a one diopter lens.

A unit for measuring the refractive power of a lens.

Measurement of optical acuity

A diopter is a unit of measure for expressing the power of a lens or lens system. A one diopter lens has a focal distance of one meter. A two diopter lens has a focal distance of 50 centimeters. Go to Top

Unit of measurement to express the amount of nearsightedness, farsightedness, and astigmatism.

measurement unit of the refractive correction of a contact lens

unit of measurement of refractive error. A negative diopter prescription for glasses or contact lenses signifies an eye with nearsightedness and positive diopter prescription signifies an eye with farsightedness.

the unit of refracting power (bending of light rays) of a lens.

This expressed the magnifying power of a lens. It is the reciprocal of the focal length expressed in meters.

(D), unit of measure for the ability of a lens to alter the direction of a ray of light; 1 diopter will alter a ray of light 1 centimeter over a distance of 1 meter; 4 diopters (D) equals 1 power of magnification (X).

A term used to define the reciprocal focal length, commonly used for ophthalmic lenses. The inverse focal length of a lens expressed in diopters is 1000/f, where f is the focal length in millimeters.

a unit of optical measurement which refers to the ability of a lens to bend light. A 1 diopter lens bends a beam of light 1 cm at a distance of 1 meter

The part of the eyepiece on the camera that must be focused based on each individual's eyesight. There are lines in a film camera and numbers in a video camera that can be used to focus the diopter. If the diopter is not focused, the image through the camera will appear focused to the operators eye but what is being recorded will appear out of focus on screen to a different set of eyes.

Unit which measures the refractive (light-bending) power of a lens; eyecare practitioners use it in eyeglass and contact lens prescriptions. A negative number refers to nearsightedness, while a positive number refers to farsightedness. For example, someone with -8.00 diopter lenses is very nearsighted, while someone with +0.75 diopter lenses is only slightly farsighted.

A unit measurement of the degree to which light converges or diverges. Diopters are used to define a lens's refractive power. Equal to the reciprocal of the focal length of a lens (in meters), e.g., a 2-diopter lens brings parallel rays of light to a focus at half a meter.

Unit of optical measurement of a lens that equals the inverse of the focal length of the lens in meters.

Opticians unit of measure for focal length. The reciprocal of the focal length in meters; the unit of “power of a lens”.

The unit of refractive power.

Unit of measure used in optics to measure the refractive power of a lens and the eye, considered to be an optical system. ( diotprie, n.f)

A unit of measure of the refractive power if a lens. A one-diopter lens will focus parallel light rays one meter from the lens and a two-diopter lens will focus one-half of a meter from the lens. A plus 1.0 diopter lens is convex and will converge the light rays so they focus as a visible image 1 meter past the lens. A minus 1.0 diopter lens is concave and will diverge or spread light. The minus lens will not actually focus as a visible image on an optics table. Its image is known as a virtual image and if the diverging rays were followed to their point of origin, they would focus one meter in front of the minus lens.

measurement of the degree to which light converges or diverges; also a measurement of lens refractive power.

the unit of power (strength) for a lens; the reciprocal of the focal length, in meters (see equation 23.1)

A measurement of the refractive power of a lens element, as a portion of a meter.

A unit which measures the amount of myopia and astigmatism of the eye.

Unit of measure for optical strength or refractive power of glasses or contact lenses.

Unit of power used in describing the optical properties of lenses. A one diopter lens brings rays of light to a focus at one meter. The higher the dioptric power, the stronger the lens.

Unit of measurement for the power of a lens or of refractive error

the measurement of refractive error. (See Refractive Errors) A negative diopter value signifies an eye with myopia (nearsightedness) and positive diopter value signifies an eye with hyperopia (farsightedness).

unit used to express the power of a lens. It is the reciprocal of the focal length expressed in meters.

This is a unit of measurement that helps you determine how much you need to alter a lens to bend or refract light rays to get the proper focus.

Molecular Systemic Monovision

Mediator Stroma Membrane Substrate

Adjustable part of camera viewfinder which compensates for individuals eyesight.

a value that is metric and universal worldwide

An adjustment that compensates for the differences in users' vision.