Eye
Eyes are organs that detect light and convert it into electro-chemical impulses in neurons. The simplest photoreceptor cells in conscious vision connect light to movement. In higher organisms the eye is a complex optical system which collects light from the surrounding environment, regulates its intensity through a diaphragm, focuses it through an adjustable assembly of lenses to form an image, converts this image into a set of electrical signals, and transmits these signals to the brain through complex neural pathways that connect the eye via the optic nerve to the visual cortex and other areas of the brain. Eyes with resolving power have come in ten fundamentally different forms, and 96% of animal species possess a complex optical system. Image-resolving eyes are present in molluscs, chordates and arthropods.
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Famous quotes containing the word eye:
“How should the world be luckier if this house,
Where passion and precision have been one
Time out of mind, became too ruinous
To breed the lidless eye that loves the sun?”
—William Butler Yeats (1865–1939)
“The gods are partial to no era, but steadily shines their light in the heavens, while the eye of the beholder is turned to stone. There was but the sun and the eye from the first. The ages have not added a new ray to the one, nor altered a fibre of the other.”
—Henry David Thoreau (1817–1862)