The pupillary light reflex is a reflex that controls the diameter of the pupil, in response to the intensity (luminance) of light that falls on the retina of the eye, thereby assisting in adaptation to various levels of darkness and light, in addition to retinal sensitivity. Greater intensity light causes the pupil to become smaller (allowing less light in), whereas lower intensity light causes the pupil to become larger (allowing more light in). Thus, the pupillary light reflex regulates the intensity of light entering the eye.
Read more about Pupillary Light Reflex: Mechanism, A Mathematical Description, Clinical Significance
Famous quotes containing the words light and/or reflex:
“Men’s hearts are cold. They are indifferent. Not all the coal that is dug warms the world. It remains indifferent to the lives of those who risk their life and health down in the blackness of the earth; who crawl through dark, choking crevices with only a bit of lamp on their caps to light their silent way; whose backs are bent with toil, whose very bones ache, whose happiness is sleep, and whose peace is death.”
—Mother Jones (1830–1930)
“The theatre is the involuntary reflex of the ideas of the crowd.”
—Sarah Bernhardt (1845–1923)