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Pupillometer, also spelled pupilometer, is a medical device intended to measure by reflected light the size of the pupil of the eye. [1] In addition to measuring pupil size, current automated pupillometers may also be able to characterize pupillary light reflex .
In 2019, the first smartphone based pupillometer was released as an accurate and economical way to determine pupil size and dynamic response objectively. [8] However, another study has shown the necessary use of an opaque eyecup as pupillary light reflex is affected by ambient light. [ 7 ]
An optical sensor converts light rays into electronic signals. It measures the physical quantity of light and then translates it into a form readable by an instrument. An optical sensor is generally part of a larger system that integrates a source of light, a measuring device, and the optical sensor. This is often connected to an electrical ...
First, a single test light of constant size and brightness is used. The test light is moved towards the center of vision from the periphery until it is first detected by the patient. This is repeated by approaching the center of vision from different directions. Repeating this enough will establish a boundary of vision for that target.
a) The sensor has an electronic chip. The measuring signal is directly converted into a digital signal inside the sensor. The data transmission through the cable is also digital. This digital data transmission is unaffected by cable length, cable resistance or impedance, and is not influenced by electromagnetic noise. Standard cables can be used.
The tonometer tip rests on the cornea with a constant appositional force of one gram. When the sensor is subjected to a change in pressure, the electrical resistance is altered and the tonometer's computer calculates a change in pressure according to the change in resistance. A complete measurement cycle requires about eight seconds of contact ...
When the sensor system is linear, its spectral sensitivity and spectral responsivity can both be decomposed with similar basis functions. [8] When a system's responsivity is a fixed monotonic nonlinear function, that nonlinearity can be estimated and corrected for, to determine the spectral sensitivity from spectral input–output data via ...
This type of instrument, which is commonly referred to as a pupillometer, albeit incorrectly, [11] may also be used to verify PD measurements taken with a PD stick. [12] As an alternative to having PD measured by an ECP, a variety of web and mobile (Android and iOS) apps are now widely available. Web apps are used by a variety of online sellers ...