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Using a phoropter to determine a prescription for eyeglasses. An eyeglass prescription is an order written by an eyewear prescriber, such as an optometrist, that specifies the value of all parameters the prescriber has deemed necessary to construct and/or dispense corrective lenses appropriate for a patient.
A flange is a protruded ridge, lip or rim, either external or internal, that serves to increase strength (as the flange of a steel beam such as an I-beam or a T-beam); for easy attachment/transfer of contact force with another object (as the flange on the end of a pipe, steam cylinder, etc., or on the lens mount of a camera); or for stabilizing and guiding the movements of a machine or its ...
In 1938, President Roosevelt signed the Wagner-O'Day Act which directed the government to purchase products manufactured by blind Americans. [3] Robert Irwin, who was the executive director of the American Foundation for the Blind, and Peter Salmon, the assistant director for the Industrial Home for the Blind, promoted the bill in Washington, D.C. [3] This act gave non-profit organizations for ...
Man with glasses. A woman with glasses. Glasses, also known as eyeglasses or spectacles, are vision eyewear with clear or tinted lenses mounted in a frame that holds them in front of a person's eyes, typically utilizing a bridge over the nose and hinged arms, known as temples or temple pieces, that rest over the ears for support.
The ASME B16 Standardization of Valves Flanges, Fittings and Gaskets Committee, which operates under ASME’s Board on Pressure Technology Codes and Standards is responsible for standards covering valves, flanges, pipe fittings, gaskets and valve actuators for use in pressure services.
Compact disc players use an astigmatic lens for focusing. When one axis is more in focus than the other, dot-like features on the disc project to oval shapes. The orientation of the oval indicates which axis is more in focus, and thus which direction the lens needs to move.
The ability to give sight to a blind person via a bionic eye depends on the circumstances surrounding the loss of sight. For retinal prostheses, which are the most prevalent visual prosthetic under development (due to ease of access to the retina among other considerations), patients with vision loss due to degeneration of photoreceptors (retinitis pigmentosa, choroideremia, geographic atrophy ...
Diagram illustrating the flange focal length of an SLR–type and a mirrorless–type camera. For an interchangeable lens camera, the flange focal distance (FFD) (also known as the flange-to-film distance, flange focal depth, flange back distance (FBD), flange focal length (FFL), back focus [1] or register, depending on the usage and source) of a lens mount system is the distance from the ...