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[9] [10] He was the first person to explain that vision occurs when light bounces on an object and then is directed to one's eyes. [11] Leonardo da Vinci (1452–1519) is believed to be the first to recognize the special optical qualities of the eye. He wrote "The function of the human eye ... was described by a large number of authors in a ...
There are two luminous efficiency functions in common use. For everyday light levels, the photopic luminosity function best approximates the response of the human eye. For low light levels, the response of the human eye changes, and the scotopic curve applies. The photopic curve is the CIE standard curve used in the CIE 1931 color space.
The human eye is an organ which reacts to light for several purposes. As a conscious sense organ, the eye allows vision. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth. The human eye can distinguish about 10 million colors. [3]
The stimulus modality for vision is light; the human eye is able to access only a limited section of the electromagnetic spectrum, between 380 and 760 nanometres. [3] Specific inhibitory responses that take place in the visual cortex help create a visual focus on a specific point rather than the entire surrounding.
Vision is often one of the first senses affected by aging. A number of changes occur with aging: Over time, the lens becomes yellowed and may eventually become brown, a condition known as brunescence or brunescent cataract. Although many factors contribute to yellowing, lifetime exposure to ultraviolet light and aging are two main causes.
Alhazen was the first person to explain that vision occurs when light reflects from an object into one's eyes. [7] The rise of rationalist physics in the 17th century led to a novel version of the intromissionist theory that proved extremely influential and displaced any legacies of the old emissive theories.
The size of the pupil, which controls the amount of light entering the eye, is adjusted by the iris' dilator and sphincter muscles. Light energy enters the eye through the cornea, through the pupil and then through the lens. The lens shape is changed for near focus (accommodation) and is controlled by the ciliary muscle.
The Stiles–Crawford effect of the second kind is the phenomenon where the observed color of monochromatic light entering the eye near the edge of the pupil is different compared to that for the same wavelength light entering near the center of the pupil, regardless of the overall intensities of the two lights.