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Corrective lens. A corrective lens is a transmissive optical device that is worn on the eye to improve visual perception. The most common use is to treat refractive errors: myopia, hypermetropia, astigmatism, and presbyopia. Glasses or "spectacles" are worn on the face a short distance in front of the eye.
The Donabedian model is a conceptual model that provides a framework for examining health services and evaluating quality of health care. [ 1] According to the model, information about quality of care can be drawn from three categories: “structure,” “process,” and “outcomes." [ 2] Structure describes the context in which care is ...
e. Evidence-based nursing ( EBN) is an approach to making quality decisions and providing nursing care based upon personal clinical expertise in combination with the most current, relevant research available on the topic. This approach is using evidence-based practice (EBP) as a foundation. EBN implements the most up to date methods of ...
Abbe number. In optics and lens design, the Abbe number, also known as the V-number or constringence of a transparent material, is an approximate measure of the material's dispersion (change of refractive index versus wavelength), with high values of V indicating low dispersion. It is named after Ernst Abbe (1840–1905), the German physicist ...
An optical instrument is said to be diffraction-limited if it has reached this limit of resolution performance. Other factors may affect an optical system's performance, such as lens imperfections or aberrations, but these are caused by errors in the manufacture or calculation of a lens, whereas the diffraction limit is the maximum resolution ...
This has been a tough question to answer over the years, especially as high-quality studies controlled for bias and external factors have been lacking, says Stephen Vogel, M.D., a family medicine ...
Chromatic aberration. Focal length of lens varies with the color of light. In optics, chromatic aberration ( CA ), also called chromatic distortion, color aberration, color fringing, or purple fringing, is a failure of a lens to focus all colors to the same point. [ 1][ 2] It is caused by dispersion: the refractive index of the lens elements ...
The model was developed by Dr. Kathleen Stevens at the Academic Center for Evidence-Based Practice located at the University of Texas Health Science Center at San Antonio. [3] The model has been represented in many nursing textbooks , used as part of an intervention to increase EBP competencies, and as a framework for instruments measuring EBP ...