COLOR BLINDNESS IS AN INHERITED DEFECT OF VISION, RESULTING IN A PERSON'S INABILITY  TO
DISTINGUISH  BETWEEN SPECIFIC COLORS.
PARTIAL COLOR BLINDNESS IS MORE COMMON THAN TOTAL COLOR BLINDNESS, IN WHICH A PERSON SEES EVERYTHING AS SHADES OF GRAY
(GREY). THE MOST COMMON FORM OF PARTIAL
COLOR BLINDNESS LEADS TO INABILITY TO
DISTINGUISH  BETWEEN RED  AND GREEN AND RARELY BETWEEN BLUE AND YELLOW.

COLOR BLINDNESS IS A FAIRLY COMMON CONDITION
WHICH OCCURS MORE IN MEN THAN WOMEN, BUT IT IS
RARELY A SERIOUS DISADVANTAGE TO THOSE AFFECTED.
APPROXIMATELY ONE IN 20 MEN AND ONE IN 200 WOMEN ARE AFFECTED .SOME STUDIES SUGGEST THAT ABOUT EIGHT PERCENT OF THE WORLD'S MALE POPULATION AND LESS THAN ONE PERCENT OF FEMALE
POPULATION ARE AFFECTED .MANY PEOPLE ARE UNAWARE THEY ARE COLOR BLIND UNTIL THEIR  EYES HAVE BEEN TESTED .

THE RETINA COMPROMISES  TWO TYPES  OF PHOTORECEPTORS , RODS AND CONES. ALTHOUGH THE  RODS ARE MORE NUMEROUS, SOME 120 MILLION, AND ARE MORE SENSITIVE THAN THE CONES, THEY ARE NOT HOW-EVER, SENSITIVE TO COLOR. RODS ARE RESPONSIBLE FOR VISION AT LOW LIGHT LEVELS
(SCOTOPIC  VISION) AND THEY DO NOT MEDITATE COLOR VISION AND HAVE A LOW SPATIAL ACUITY  THE SIX OR SEVEN MILLION CONES THAT PROVIDE THE EYE'S COLOR SENSITIVITY ARE MUCH MORE  CONCENTRATED IN THE CENTRAL YELLOW SPOT KNOWN AS THE MACULA.

BEING ACTIVE AT HIGHER LIGHT LEVELS (PHOTOPIC VISION) CONES ARE CAPABLE OF COLOR VISION AND ARE RESPONSIBLE FOR HIGH SPATIAL ACUITY. IN SIMPLE TERMS IT MAY BE SAID  THAT CONES  REQUIRE BRIGHTER LIGHT TO FUNCTION THAN RODS.

RED ,GREEN AND HAVE THEIR CORRESPONDING  WAVELENGTHS . RED WAVELENGTHS  ARE LONGEST, FOLLOWED BY GREEN WAVELENGTHS (MEDIUM) AND BLUE COLOR IS MADE UP OF SHORTER  WAVELENGTHS .

THEY ARE RED , BLUE AND GREEN CONES WHICH ARE SENSITIVE TO THOSE COLORS  AND COMBINATIONS  OF THEM. IF THE CONES DO NOT WORK PROPERLY OR IF THERE IS NO RIGHT COMBINATION, THE BRAIN DOES NOT GET THE RIGHT MESSAGE ABOUT THE COLORS YOU ARE SEEING.

THE VISIBLE COLORS FROM SHORTEST TO LONGEST WAVELENGTH  ARE VIOLET, BLUE , GREEN , YELLOW , ORANGE AND RED.
THE VISIBLE RED  LIGHT HAVING A WAVELENGTH OF ABOUT 650 NANOMETERS  IS RESPONSIBLE  FOR THE PRESENCE  OF RED OR ORANGE COLOR AT SUNRISE AND SUNSET, BECAUSE THE WAVELENGTHS  ASSOCIATED  WITH THESE COLORS ARE LESS EFFICIENTLY  SCATTERED  BY THE ATMOSPHERE THAN THE SHORTER  WAVELENGTH  COLORS SUCH AS  BLUE OR PURPLE.

THE VISIBLE GREEN LIGHT  HAVING A WAVELENGTH  OF ABOUT 510 NM MAKES THE GRASS APPEAR GREEN BECAUSE ALL THE COLORS IN THE VISIBLE PART OF SPECTRUM  ARE ABSORBED  INTO THE LEAVES  OF THE GRASS APPEARS GREEN

THE VISIBLE BLUE LIGHT HAVING A WAVELENGTH  OF ABOUT 475 NM ARE SCATTERED  MORE EFFICIENTLY  BY THE MOLECULES  IN THE ATMOSPHERE WHICH CAUSE THE SKY TO APPEAR BLUE.

PEOPLE WHO ARE BORN BLIND DO NOT SEE IMAGES IN DREAMS, BUT HAVE DREAMS VIVID INVOLVING  THEIR  OTHER SENSES  OF SOUND, SMELL, TOUCH AND EMOTION.

COLOR BLINDNESS CAUSED  BY A DISEASE  OF THE RETINA OR OPTIC NERVE IS PROGRESSIVE AND ASSOCIATED  WITH A GENERAL DETERIORATION  OF VISION, UNLIKE INHERITED  VARIETY  WHERE THE ABILITY  TO SEE DETAIL IS UNAFFECTED  AND THE CONDITION NEVER WORSEN.IT IS TESTED WITH ISHIHARA CHART NORMALLY THEIR ARE MEANS OF TESTING COLOUR BLINDNESS.

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s.s.venkateshwar, Andaman and Nicobar Islands