light reflex


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light reflex

[′līt ‚rē‚fleks]
(physiology)
The postural orientation response of certain aquatic forms stimulated by the source of light; receptors may be on the ventral or dorsal surface.
The response in which the pupil dilates when light levels are lowered, and constricts when light levels are raised.
References in periodicals archive ?
Yin, "Transient pupillary light reflex in relation to fundus autofluorescence and dark-adapted perimetry in typical retinitis pigmentosa," Ophthalmic Research, vol.
Certain pathophysiological changes can influence the pupillary aperture; these include the pupillary light reflex mechanism, the tone of SNS or PNS including their autonomic ganglion, and pathologies of the midbrain around the regions of the cerebral aqueduct of Sylvius including the regions of tectum and tegmentum, hypothalamic region, limbic system, and higher centres.
The pupillary light reflex measurement was performed on both eyes, which were subjected to a series of 5 flashes at 30-s intervals.
The color from left to right indicated that the light reflex intensity was from weak to strong according to the indication of the color scale.
The squint examination involves observation and a light torch test looking at the light reflexes of both corneas (Hirschberg test) which can give you clues to a deviated eye.
The surface dwelling Labidocera aestiva responded to all wavelength stimuli tested with a higher mean percentage of individuals undergoing a dorsal light reflex than in the dark control (Fig.
For the light reflex, the parameters measured were the latency (time elapsed between the onset of stimulus and onset of response), amplitude (distance between pre-stimulus resting pupil size and the deepest trough of the response), 75% recovery time (time taken from the peak of the response to obtain 75% recovery), and the maximum constriction velocity ([V.sub.cm]) (see Figure 1: top).
On admission, neurologic physical examination showed dysarthria, bilateral miosis, slow pupillary light reflex, weakened pharyngeal reflex, reduction in the right limb strength (right arm strength grade 4/5, right leg strength grade 2/5), and hemihypesthesia of the right limb.
Direct pupillary light reflex, menace response, and palpebral reflex were present in all birds.
Background: Trained medical practitioners have been assessing the pupillary light reflex for more than 2 millennia.
Ocular examination to access the eye functionality revealed presence of direct papillary light reflex, menace response and dazzle reflexes.