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