Jay Neitz
Encyclopedia
Jay Neitz is professor of ophthalmology
and a color vision
researcher at the University of Washington
in Seattle, Washington
in the United States
.
s in the retina – blue
, green
and red
-- can pick up about 100 different gradations of color. But, he says, the brain can combine those variations exponentially, multiplying each new variety of cone by 100, so that the average human trichromat
can distinguish about one million different hues.
This means that a monochromat
can see 100 different colors, a dichromat
can see 10,000 different colors, a trichromat
can see 1,000,000 different colors, a tetrachromat
can see 100,000,000 different colors, and a pentachromat
can see 10,000,000,000 different colors.
and began training in 1999 two dichromat
ic squirrel monkey
s. After five months of gene therapy
treatment, the monkeys began to acquire trichromat
ic color vision. They say this almost seemed to suddenly occur overnight. After that, they spent a year and a half to test the monkeys' ability to discern 16 hues.
can be cured. "This is also another example of how utterly plastic the visual system is to change," Jacobs said. "The nervous system can extract information from alterations to photopigments and make use of it almost instantaneously."
are sufficiently plastic, it may be possible to use gene therapy to replace missing photopigment
s in the eyes of color blind humans."
Neitz further states that since apparently "the neural circuits can handle even higher dimensions of color vision that could come from artificially adding a fourth cone type, it is possible that gene therapy could also be used to extend normal human color vision", making human trichromats into tetrachromats.
precursors to the earliest eye
s probably appeared between about 800 and 1100 million
years ago (MYA).”
Ophthalmology
Ophthalmology is the branch of medicine that deals with the anatomy, physiology and diseases of the eye. An ophthalmologist is a specialist in medical and surgical eye problems...
and a color vision
Color vision
Color vision is the capacity of an organism or machine to distinguish objects based on the wavelengths of the light they reflect, emit, or transmit...
researcher at the University of Washington
University of Washington
University of Washington is a public research university, founded in 1861 in Seattle, Washington, United States. The UW is the largest university in the Northwest and the oldest public university on the West Coast. The university has three campuses, with its largest campus in the University...
in Seattle, Washington
Seattle, Washington
Seattle is the county seat of King County, Washington. With 608,660 residents as of the 2010 Census, Seattle is the largest city in the Northwestern United States. The Seattle metropolitan area of about 3.4 million inhabitants is the 15th largest metropolitan area in the country...
in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
.
Cone cells and the numbers of colors an organism can see
According to Jay Neitz, each of the three standard color-detecting cone cellCone cell
Cone cells, or cones, are photoreceptor cells in the retina of the eye that are responsible for color vision; they function best in relatively bright light, as opposed to rod cells that work better in dim light. If the retina is exposed to an intense visual stimulus, a negative afterimage will be...
s in the retina – blue
Blue
Blue is a colour, the perception of which is evoked by light having a spectrum dominated by energy with a wavelength of roughly 440–490 nm. It is considered one of the additive primary colours. On the HSV Colour Wheel, the complement of blue is yellow; that is, a colour corresponding to an equal...
, green
Green
Green is a color, the perception of which is evoked by light having a spectrum dominated by energy with a wavelength of roughly 520–570 nanometres. In the subtractive color system, it is not a primary color, but is created out of a mixture of yellow and blue, or yellow and cyan; it is considered...
and red
Red
Red is any of a number of similar colors evoked by light consisting predominantly of the longest wavelengths of light discernible by the human eye, in the wavelength range of roughly 630–740 nm. Longer wavelengths than this are called infrared , and cannot be seen by the naked eye...
-- can pick up about 100 different gradations of color. But, he says, the brain can combine those variations exponentially, multiplying each new variety of cone by 100, so that the average human trichromat
Trichromat
Trichromacy or trichromaticism is the condition of possessing three independent channels for conveying color information, derived from the three different cone types...
can distinguish about one million different hues.
This means that a monochromat
Monochromat
Monochromacy, also known as "total color blindness", is a complete inability to distinguish colors. This is distinguished from more common forms of color blindness, in which the affected individual can perceive color differences, but cannot make the same distinctions between colors as can an...
can see 100 different colors, a dichromat
Dichromat
Dichromacy is the state of having two types of functioning color receptors, called cone cells, in the eyes. Organisms with dichromacy are called dichromats. Dichromats can match any color they see with a mixture of no more than two pure spectral lights...
can see 10,000 different colors, a trichromat
Trichromat
Trichromacy or trichromaticism is the condition of possessing three independent channels for conveying color information, derived from the three different cone types...
can see 1,000,000 different colors, a tetrachromat
Tetrachromat
Tetrachromacy is the condition of possessing four independent channels for conveying color information, or possessing four different types of cone cells in the eye...
can see 100,000,000 different colors, and a pentachromat
Pentachromat
Pentachromacy describes the capability and capacity for capturing, transmitting, processing, and perceiving five independent channels of color information through the primary visual system. Organisms with pentachromacy are termed pentachromats...
can see 10,000,000,000 different colors.
Curing color blindness in monkeys by gene therapy
Neitz and his wife Maureen Neitz, Ph.D., a professor of ophthalmology at the University of WashingtonUniversity of Washington
University of Washington is a public research university, founded in 1861 in Seattle, Washington, United States. The UW is the largest university in the Northwest and the oldest public university on the West Coast. The university has three campuses, with its largest campus in the University...
and began training in 1999 two dichromat
Dichromat
Dichromacy is the state of having two types of functioning color receptors, called cone cells, in the eyes. Organisms with dichromacy are called dichromats. Dichromats can match any color they see with a mixture of no more than two pure spectral lights...
ic squirrel monkey
Squirrel monkey
The squirrel monkeys are the New World monkeys of the genus Saimiri. They are the only genus in the subfamily Saimirinae.Squirrel monkeys live in the tropical forests of Central and South America in the canopy layer. Most species have parapatric or allopatric ranges in the Amazon, while S...
s. After five months of gene therapy
Gene therapy
Gene therapy is the insertion, alteration, or removal of genes within an individual's cells and biological tissues to treat disease. It is a technique for correcting defective genes that are responsible for disease development...
treatment, the monkeys began to acquire trichromat
Trichromat
Trichromacy or trichromaticism is the condition of possessing three independent channels for conveying color information, derived from the three different cone types...
ic color vision. They say this almost seemed to suddenly occur overnight. After that, they spent a year and a half to test the monkeys' ability to discern 16 hues.
Potential for curing color blindness in humans
According to Gerald H. Jacobs, Ph.D., a research professor of psychology at the University of California, Santa Barbara, who was not involved in the research, this means that color blindnessColor blindness
Color blindness or color vision deficiency is the inability or decreased ability to see color, or perceive color differences, under lighting conditions when color vision is not normally impaired...
can be cured. "This is also another example of how utterly plastic the visual system is to change," Jacobs said. "The nervous system can extract information from alterations to photopigments and make use of it almost instantaneously."
Possibility of turning human trichromats into tetrachromats
According to Jay Neitz, “If the neural circuits for color visionColor vision
Color vision is the capacity of an organism or machine to distinguish objects based on the wavelengths of the light they reflect, emit, or transmit...
are sufficiently plastic, it may be possible to use gene therapy to replace missing photopigment
Photopigment
Photopigments are unstable pigments that undergo a chemical change when they absorb light. The term is generally applied to the non-protein chromophore moiety of photosensitive chromoproteins, such as the pigments involved in photosynthesis and photoreception...
s in the eyes of color blind humans."
Neitz further states that since apparently "the neural circuits can handle even higher dimensions of color vision that could come from artificially adding a fourth cone type, it is possible that gene therapy could also be used to extend normal human color vision", making human trichromats into tetrachromats.
Evolutionary appearance of vision
According to Neitz, “The first appearance of the photoreceptive structures that were theprecursors to the earliest eye
Eye
Eyes are organs that detect light and convert it into electro-chemical impulses in neurons. The simplest photoreceptors in conscious vision connect light to movement...
s probably appeared between about 800 and 1100 million
years ago (MYA).”