pupillary reflex การใช้

• Emergency room physicians routinely assess the pupillary reflex because it is useful for assessing brain stem function.
• These cells do not contribute to sight directly, but are thought to support circadian rhythms and pupillary reflex.
• The variables most predictive of mortality were minimum systolic blood pressure, abnormal pupillary reflexes, and stupor / coma.
• The r-opsin melanopsin is also expressed in vertebrates, where it regulates circadian rhythms and mediates the pupillary reflex.
• Lack of the pupillary reflex or an abnormal pupillary reflex can be caused by optic nerve damage, oculomotor nerve damage, brain stem death and depressant drugs, such as barbiturates.
• Lack of the pupillary reflex or an abnormal pupillary reflex can be caused by optic nerve damage, oculomotor nerve damage, brain stem death and depressant drugs, such as barbiturates.
• The first visible finding is leukocoria, a grayish-yellow pupillary reflex that originates from a mass of unorganized tissue behind the iris, anterior chamber, cornea and intraocular pressure.
• On the converse, an aneurysm which leads to compression of the oculomotor nerve affects the superficial fibers and manifests as a third nerve palsy with loss of the pupillary reflex ( in fact, this third nerve finding is considered to represent an aneurysm until proven otherwise and should be investigated ).
• The opsin found in the photosensitive ganglion cells of the retina that are involved in various reflexive responses of the brain and body to the presence of ( day ) light, such as the regulation of circadian rhythms, pupillary reflex and other non-visual responses to light, is called melanopsin.
• Unfortunately, signs of elevated intracranial pressure, such as papilledema and loss of pupillary reflexes, are not reliable, and occur late in the disease process . subdural route is often recommended; however, the risk of complications must be weighed against the possible benefit ( 1 % fatal haemorrhage ).
• When the test is performed in an eye with an afferent pupillary defect, light directed in the affected eye will cause only mild constriction of both pupils ( due to decreased response to light from the afferent defect ), while light in the unaffected eye will cause a normal constriction of both pupils ( due to an intact efferent path, and an intact consensual pupillary reflex ).
• A final population of photosensitive ganglion cells, containing melanopsin for photosensitivity, sends information via the retinohypothalamic tract ( RHT ) to the pretectum ( pupillary reflex ), to several structures involved in the control of circadian rhythms and sleep such as the suprachiasmatic nucleus ( SCN, the biological clock ), and to the ventrolateral preoptic nucleus ( VLPO, a region involved in sleep regulation ).
• Methods that have been suggested to provide some defence against the use of fake eyes and irises include changing ambient lighting during the identification ( switching on a bright lamp ), such that the pupillary reflex can be verified and the iris image be recorded at several different pupil diameters; analysing the 2D spatial frequency spectrum of the iris image for the peaks caused by the printer dither patterns found on commercially available fake-iris contact lenses; analysing the temporal frequency spectrum of the image for the peaks caused by computer displays.