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Maddox wing. The Maddox Wing is an instrument utilized by ophthalmologists, orthoptists and optometrists in the measurement of strabismus (misalignment of the eyes; commonly referred to as a squint or lazy eye by the lay person). It is a quantitative and subjective method of measuring the size of a strabismic deviation by dissociation of the ...
Exophoria. Exophoria is a form of heterophoria in which there is a tendency of the eyes to deviate outward. [1] During examination, when the eyes are dissociated, the visual axes will appear to diverge away from one another. [2] The axis deviation in exophoria is usually mild compared with that of exotropia .
Heterophoria is an eye condition in which the directions that the eyes are pointing at rest position, when not performing binocular fusion, are not the same as each other, or, "not straight". This condition can be esophoria, where the eyes tend to cross inward in the absence of fusion; exophoria, in which they diverge; or hyperphoria, in which ...
A cover test or cover-uncover test is an objective determination of the presence and amount of ocular deviation. It is typically performed by orthoptists, ophthalmologists and optometrists during eye examinations . The two primary types of cover tests are: the alternating cover test. the unilateral cover test (or the cover-uncover test).
The term self-contained means that the SCBA is not dependent on a remote supply of breathing gas (e.g., through a long hose). They are sometimes called industrial breathing sets. Some types are also referred to as a compressed air breathing apparatus ( CABA) or simply breathing apparatus ( BA ). Unofficial names include air pack, air tank ...
Turbomolecular pump. A turbomolecular pump is a type of vacuum pump, superficially similar to a turbopump, used to obtain and maintain high vacuum. [1] [2] These pumps work on the principle that gas molecules can be given momentum in a desired direction by repeated collision with a moving solid surface. In a turbomolecular pump, a rapidly ...
Stagnation pressure is the static pressure a gas retains when brought to rest isentropically from Mach number M. [6] or, assuming an isentropic process, the stagnation pressure can be calculated from the ratio of stagnation temperature to static temperature: where: is the stagnation pressure. is the static pressure. is the stagnation temperature.
Diffusion pumps use a high speed jet of vapor to direct gas molecules in the pump throat down into the bottom of the pump and out the exhaust. They were the first type of high vacuum pumps operating in the regime of free molecular flow , where the movement of the gas molecules can be better understood as diffusion than by conventional fluid ...