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Vertex distance is the distance between the back surface of a corrective lens, i.e. glasses (spectacles) or contact lenses, and the front of the cornea. Increasing or decreasing the vertex distance changes the optical properties of the system, by moving the focal point forward or backward, effectively changing the power of the lens relative to ...
Back vertex distance BVP: Back vertex power CD: Centration distance C/D: Cup–disc ratio CF: Count fingers vision – state distance c/o or c.o. Complains of CT: Cover test c/u: Check up CW: Close work Δ: Prism dioptre D: Dioptres DC: Dioptres cylinder DNA: Did not attend DOB: Date of birth DS: Dioptres sphere DV: Distance vision DVD ...
A lensmeter or lensometer (sometimes even known as focimeter or vertometer), [1] [2] is an optical instrument used in ophthalmology. It is mainly used by optometrists and opticians to measure the back or front vertex power of a spectacle lens and verify the correct prescription in a pair of eyeglasses , to properly orient and mark uncut lenses ...
This is a documentation subpage for Template:3D glasses. It may contain usage information, categories and other content that is not part of the original template page. This template can be used in image captions to hint the reader about the anaglyphic nature of the image.
The sign convention for the optical radius of curvature is as follows: If the vertex lies to the left of the center of curvature, the radius of curvature is positive. If the vertex lies to the right of the center of curvature, the radius of curvature is negative. Thus when viewing a biconvex lens from the side, the left surface radius of ...
Positive signs indicate distances to the right of the corresponding vertex, and negative to the left. [4] For a thin lens in air, the principal planes both lie at the location of the lens. The point where they cross the optical axis is sometimes misleadingly called the optical centre of the lens. For a real lens the principal planes do not ...
Person wearing a mask, glasses and a cap. An anti-facial recognition mask is a mask which can be worn to confuse facial recognition software. This type of mask is designed to thwart the surveillance of people by confusing the biometric data. There are many different types of masks which are used to trick facial recognition technology.
Optical lens design is the process of designing a lens to meet a set of performance requirements and constraints, including cost and manufacturing limitations. Parameters include surface profile types (spherical, aspheric, holographic, diffractive, etc.), as well as radius of curvature, distance to the next surface, material type and optionally tilt and decenter.