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A pinhole occluder is an opaque disk with one or more small holes through it, used by ophthalmologists, orthoptists and optometrists to test visual acuity. The occluder is a simple way to focus light, as in a pinhole camera, temporarily removing the effects of refractive errors such as myopia. Because light passes only through the center of the ...
Pinhole glasses, also known as stenopeic glasses, are eyeglasses with a series of pinhole-sized perforations filling an opaque sheet of plastic in place of each lens. Similar to the workings of a pinhole camera , each perforation allows only a very narrow beam of light to enter the eye which reduces the size of the circle of confusion on the ...
Wide-field micrograph of a damaged 80 μm pinhole Natural pinholes formed by tree leaves – Solar eclipse of August 21, 2017 in Washington state. A pinhole is a small circular hole, as could be made with the point of a pin. In optics, pinholes with diameter between a few micrometers and a hundred micrometers are used as apertures in optical ...
An occluder is placed over the eye that is not being tested (e.g.: over the left eye, to test the right eye's vision). A pinhole occluder is then placed before the patient's eye, and their vision is then tested again (each eye separately) to determine if the patient's poor visual acuity is a result of optical irregularities, or pathological issues.
Through-hole (leaded) resistors. In electronics, through-hole technology (also spelled "thru-hole") is a manufacturing scheme in which leads on the components are inserted through holes drilled in printed circuit boards (PCB) and soldered to pads on the opposite side, either by manual assembly (hand placement) or by the use of automated insertion mount machines.
Kurt Anton Amplatz (February 25, 1924 – November 6, 2019) was an Austrian radiologist and medical device inventor. [1] He is best known for the invention of the Amplatzer Septal Occluder as well as the Amplatzer Cribriform Occluder, which is used for closing atrial septal defect, a common congenital heart defects found in infants.
Effusion from an equilibrated container into outside vacuum can be calculated based on kinetic theory. [2] The number of atomic or molecular collisions with a wall of a container per unit area per unit time (impingement rate) is given by: =. assuming mean free path is much greater than pinhole diameter and the gas can be treated as an ideal gas.
A micropipe, also called a micropore, microtube, capillary defect or pinhole defect, is a crystallographic defect in a single crystal substrate. Minimizing the presence of micropipes is important in semiconductor manufacturing , as their presence on a wafer can result in the failure of integrated circuits made from that wafer.