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Dr Vandita Shanbhag
COLOR VISION
PATHWAY FOR VISION
STRUCTURE OF RETINA
RODS AND CONES
PHOTOTRANSDUCTION IN RODS OR CONES
Why does Fovea have the best vision?
RECEPTIVE FIELDS
LATERAL INHIBITION
EVOLUTION OF COLOR SENSE
In lower invertebrate animals Photosensitive pigments
Scattered Form optic spots or fovea
In some echinoderms the photosensitive cells show surface protrusions known as
optic rods In insects
HISTORY AND THEORIES
Aristotle (in 4th century B.C.) Sir Isaac Newton (in 1663) George Palmer (in 1777)
Thomas Young (in 1802) William Wollastan
Violet
Yellow
Red
Clerk Maxwell (in 1850) Hermann von Helmholtz
TRICHROMATIC THEORY
3 types of cones with 3 different photopigments
Each cone is maximally sensitive to one primary color
Peak sensitivities occur Blue at 445nm Green at 535nm Red at 570nm
THE OPPONENT THEORY
Ewald Hering
Trichromatic theory couldn’t explain certain aspects
S M L
THEORY OF DOMINATOR-MODULATOR
Ragnar Arthur Granit
PRINCIPLE OF SPECIFIC ENERGY
Johannes Muller
COLOR VISION- A HIGHER FUNCTION
TESTS FOR COLOR VISION
In 17th century, Turberville used color naming tests.
In 1837 August Seebeck used a set of more than 300 colored papers and let people match.
In 1877, Holmgren developed wool matching test
Rayleigh color match
ANAMOLOSCOPES
In 1907 the Nagel anomaloscope was introduced and is still known as one of the best.
Neitz anomaloscope Pickford-Nicolson
anomaloscope
PSEUDOCHROMATIC PLATES
Dr. J. Spilling published the
first painted set of
pseudoisochromatic plates
In 1917, Ishihara Charts
LANTERNS
Edridge Green Lantern Test Holmes-Wright lanterns: Farnsworth lantern (Falant) Beyne lantern Giles-Archer lanterns
Farnsworth- Munsell100 hue test
Farnsworth 15D test
The City University Test
FUTURE OF COLOR VISION TESTING
Computer monitor based tests?
COLOR BLINDNESS
John Dalton
Daltonism
TYPES OF COLOR BLINDNESS
Monochromats Rod monochromacy Cone monochromacy
Dichromats
Trichromats
GENES INVOLVED
DAILY HANDICAP
A Sunburn can’t really be seen, only if the skin is almost glowing.
If meat is cooked can’t be told by its color. There is no difference between the colors for vacant (green) and
occupied (red). Flowers and fruits can’t be that easily spotted sometimes. And you can’t tell if a fruit or vegetable is ripe or not yet. Every electrical device which uses LED lights to indicate
something is a permanent source of annoyance. Colored maps and graphics can sometimes be very hard to
decipher. By far the biggest issue is matching colors and specially matching
clothes.
PROFESSIONAL HANDICAP
Air line Pilots Air traffic controllers Fire fighters Police officers Train drivers Electrical/Electronic
Engineers
IMPLICATION IN MEDICINE
TREATMENT
The first eyeborg was created in England in 2003 by Adam Montandon in collaboration with colourblind artist Neil Harbisson
In 2007, Peter Kese, a software developer from Kranj, Slovenia, made further developments to the eyeborg by increasing the number of color hues to 360 and adding color saturation through different volume levels.[5] In 2009, Matias Lizana, a student from Universitat Politècnica de Catalunya developed the eyeborg into a chip as part of his final year project.[6] The chip allows users to have the device implanted and to hear colors beyond the limits of human perception such as infrared and ultraviolet.[7]
he eyeborg works with a head mounted camera that picks up the colours directly in front of a person, and converts them in real-time into sound waves.[24] Neil memorised the frequencies related to each colour: high frequency hues are high-pitched, while low frequency hues sound bolder.
THANK YOU