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The same water in a smaller bucket looks only slightly cyan, [1] and observing the water at close range makes it appear colorless to the naked eye. The intrinsic color of liquid water may be demonstrated by looking at a white light source through a long pipe that is filled with purified water and closed at both ends with a transparent window.
The irises of human eyes exhibit a wide spectrum of colours. Eye color is a polygenic phenotypic trait determined by two factors: the pigmentation of the eye's iris [1] [2] and the frequency-dependence of the scattering of light by the turbid medium in the stroma of the iris. [3]: 9
The eye is usually patched on the day of surgery and use of an eye shield at night is often suggested for several days after surgery. [ 52 ] In all types of surgery, the cataractous lens is removed and replaced with an artificial lens, known as an intraocular lens , which stays in the eye permanently.
Bulging eyes: where the eye (one or both) protrudes or distends out of its orbit. Left untreated, bulging eyes may lead to eye dryness, pain and vision loss [3] Cytomegalovirus (CMV) Retinitis: This is an inflammation of the retina caused by infection, which can result in blindness.
The pupil of the human eye can range in size from 2 mm to over 8 mm to adapt to the environment. The human eye can detect a luminance from 10 −6 cd/m 2, or one millionth (0.000001) of a candela per square meter to 10 8 cd/m 2 or one hundred million (100,000,000) candelas per square meter.
The vertebrate eye is usually either optimised for underwater vision or air vision, as is the case in the human eye. The visual acuity of the air-optimised eye is severely adversely affected by the difference in refractive index between air and water when immersed in direct contact.
Monochromacy (from Greek mono, meaning "one" and chromo, meaning "color") is the ability of organisms to perceive only light intensity without respect to spectral composition. Organisms with monochromacy lack color vision and can only see in shades of grey ranging from black to white. Organisms with monochromacy are called monochromats.
Trichromatic color vision is the ability of humans and some other animals to see different colors, mediated by interactions among three types of color-sensing cone cells. The trichromatic color theory began in the 18th century, when Thomas Young proposed that color vision was a result of three different photoreceptor cells .