LESSON 4: COLOR VISION DEFICIENCY

ANOMALOUS TRICHROMACY

- In people with this condition all of their three cone types are used to perceive light colours but one type of cone perceives light slightly out of alignment, so that there are three different types of effect produced depending upon which cone type is 'faulty'. (TYPE OF COLOR BLINDNESS)

TRICHROMACY

- Normal colour vision uses all three types of light cones correctly and is known as _________. - People with normal colour vision are known as trichromats. (TYPE OF COLOR BLINDNESS)

ANOMALOUS TRICHROMACY

- People with 'faulty' trichromatic vision will be colour blind to some extent and are known as _________. - In people with this condition all of their three cone types are used to perceive light colours but one type of cone perceives light slightly out of alignment, so that there are three different types of effect produced depending upon which cone type is 'faulty'. (TYPE OF COLOR BLINDNESS)

MONOCHROMACY (achromatopsia)

- People with THIS vision can see no colour at all and their world consists of different shades of grey ranging from black to white, rather like only seeing the world on an old black and white television set.

DICHROMACY

- People with dichromatic colour vision have only two types of cones which are able to perceive colour i.e. they have a total absence of function of one cone type. Lack of ability to see colour is the easiest way to explain this condition but in actual fact it is a specific section of the light spectrum which can't be perceived. (TYPE OF COLOR BLINDNESS)

COLOR BLINDNESS OR CVD

- The inability to perceive differences between some of the colors that others can distinguish.

COLOR BLINDNESS OR CVD

- is not a form of blindness at all, but a deficiency in the way you see color. With this vision problem, you have difficulty distinguishing certain colors, such as blue and yellow or red and green.

chronic illnesses accidents medications Industrial or Environmental Chemicals AGE

A c q u i r e d COLOUR VISION DEFIENCY

Alzheimer's disease, diabetes mellitus, glaucoma, leukaemia, liver disease, chronic alcoholism, macular degeneration, multiple sclerosis, Parkinson's disease, sickle cell anaemia.

Chronic Illnesses, which can lead to colour blindness include

COLOR BLINDNESS CAUSE

Color blindness occurs when light-sensitive cells (rods & cones) in the retina fail to respond appropriately to variations in wavelengths of light that enable people to see an array of colors.

red, green, and blue

Color perception in the human eye is build up by three different types of cones. Each type is sensitive to a certain wavelength of light and every perceived color is therefore a mixture of stimuli of those three cone types

COLOR VISION

Color vision is the ability of an organism or machine to distinguish objects based on the wavelengths (or frequencies) of the light they reflect, emit, or transmit.

PROTANOPIA DEUTERANOPIA TRITANOPIA Protanomaly Deuteranomaly Tritanomaly

DIFFERENT COLOR VISIONS

TRICHROMACY ANOMALOUS TRICHROMACY DICHROMACY MONOCHROMACY (achromatopsia)

TYPES OF COLOR BLINDNESS

JOHN DALTON

He claimed, that a colored liquid inside the eyeball is the source for a different color perception. This was proved wrong only after his death, when his eyes were examined and no such liquid was found.

trichromats

People with normal colour vision are known as

John Dalton in 1793

The first scientific paper entitled "Extraordinary facts relating to the vision of colours" about color blindness was written by

DIAGNOSIS FOR COLOR BLINDNESS

Used of ISHIHARA TEST Is a color perception test for red-green color deficiencies, the first in a class of successful color vision tests called PSEUDO-ISOCHROMATIC PLATES It was named after its designer, Dr. Shinobu Ishihara, a professor at the University of Tokyo, who first published his test in 1917

Deuteranomaly

a reduced sensitivity to green light and is the most common form of color blindness

Protanomaly

a reduced sensitivity to red light

Color Blindness

is a common hereditary (inherited) condition which means it is usually passed down from your parents.

COLOR BLINDNESS OR CVD

perceiving a narrower color spectrum compared to somebody with normal color vision.

Tritanomaly

reduced sensitivity to blue light and is extremely rare

TRITANOPIA

unable to perceive any 'blue' light

DEUTERANOPIA

unable to perceive any 'green' light

PROTANOPIA

unable to perceive any 'red' light

Thomas Young and Hermann von Helmholtz

were the first who described the trichromatic color vision. And once a theory for human color vision was ready, the basics of color vision deficiency weren't far away.