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White light is dispersed by a prism into the colors of the visible spectrum. The visible spectrum is the band of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called visible light (or simply light). The optical spectrum is sometimes considered to be the same as the ...
Visual acuity with Near chart without correctors Visual acuity with eye chart at Near 15.7 inches (400 mm) and without (sc: Latin sine correctore) correctors (spectacles); Ncc is with (cc: Latin cum correctore) correctors. See Visual_acuity#Legal_definitions: VA OS Left visual acuity VA OD Right visual acuity VDU Visual display unit VF Visual field
Eye color. Eye color is a polygenic phenotypic trait determined by two factors: the pigmentation of the eye 's iris [1] [2] and the frequency-dependence of the scattering of light by the turbid medium in the stroma of the iris. [3] : 9. In humans, the pigmentation of the iris varies from light brown to black, depending on the concentration of ...
Prism (optics) An optical prism is a transparent optical element with flat, polished surfaces that are designed to refract light. At least one surface must be angled — elements with two parallel surfaces are not prisms. The most familiar type of optical prism is the triangular prism, which has a triangular base and rectangular sides.
The ChromaDepth eyeglasses contain special view foils, which consist of microscopically small prisms. This causes the image to be translated a certain amount that depends on its color. If one uses a prism foil now with one eye but not on the other eye, then the two seen pictures – depending upon color – are more or less widely separated.
A good procedure is a chart, analogous to the familiar Snellen visual acuity chart, in which one letter in each row differs in depth (front or behind) sequentially increasing in difficulty. For children the fly test is ideal: the image of a fly is transilluminated by polarized light; wearing polarizing glasses the wing appears at a different ...
Aberrations of the eye. The eye, like any other optical system, suffers from a number of specific optical aberrations. The optical quality of the eye is limited by optical aberrations, diffraction and scatter. [1] Correction of spherocylindrical refractive errors has been possible for nearly two centuries following Airy's development of methods ...
Snellen chart. Purpose. Snellen chart is used to estimate visual acuity (last three rows are 20/15, 20/13 and 20/10) A Snellen chart is an eye chart that can be used to measure visual acuity. Snellen charts are named after the Dutch ophthalmologist Herman Snellen who developed the chart in 1862 as a measurement tool for the acuity formula ...
Lea test. logMAR chart. An eye chart is a chart used to measure visual acuity comprising lines of optotypes in ranges of sizes. Optotypes are the letters or symbols shown on an eye chart. [1] Eye charts are often used by health care professionals, such as optometrists, physicians and nurses, to screen persons for vision impairment.
Peripheral vision, or indirect vision, is vision as it occurs outside the point of fixation, i.e. away from the center of gaze or, when viewed at large angles, in (or out of) the "corner of one's eye". The vast majority of the area in the visual field is included in the notion of peripheral vision. "Far peripheral" vision refers to the area at ...