Colour Vison Deficency (CVD)

1. COLOUR BLINDNESS

2. COLOUR VISION DEFICIENCY

3. What Is Colour Vision Deficiency? Causes Of Colour Vision Deficiency Types Of Colour Vision Deficiency Treatments Of Colour Vision Deficiency Ishihara’s Test Conclusion

4. What Is Colour Vision Deficiency? Colour blindness, or colour vision deficiency, is the inability or decreased ability to see colour, or perceive colour differences, under normal lighting conditions. This condition results from an absence of colour sensitive pigment in the cone cells of the retina, the nerve layer at the back of the eye.

5. What Is Colour Vision Deficiency? • Cones are the coloured light receptors in back of the eye: Red light receptors, Blue light receptors and Green light receptors. • Colour blindness occurs when one or more of the cone types are defected.

6. Causes Of Colour Vision Deficiency Red/Green or Blue colour blindness is passed down from parents. The gene responsible is on “ X ” chromosome. mutations capable of causing colour blindness originate from at least 19 different chromosomes and many different genes More males are affected the females are basically carrier There is 50% chance of mother passing this condition to her son ( Genetic condition )

7. Causes Of Colour Vision Deficiency ( 50% Chance of CVD ) ♂ ♀ X X XY X Y XY X X XX Case - 1 ( 50% Chance of Carrier ) ( Genetic condition )

8. Causes Of Colour Vision Deficiency ( 50% Chance of CVD ) ♂ ♀ X X X Y XY X Y XX X X Case - 2 ( 50% Chance of CVD ) ( Genetic condition )

9. Causes Of Colour Vision Deficiency ( All are CVD ) ♂ ♀ XX XY X Y X Y X X X X Case - 3 ( All are Carrier ) ( Genetic condition )

10. Causes Of Colour Vision Deficiency ♂ ♀ XX X Y X Y X Y XX XX Case - 4 ( All are CVD ) ( All are CVD ) ( Genetic condition )

11. Causes Of Colour Vision Deficiency In our eye there are two types of light sensitive cell 1. Rods 2. cones Both found in retina which is a layer at the back of eye it processes images. The rods are responsible for vision in night as work in low light condition ( cannot distinguish different wavelength of light) The cones are responsible for colour discrimination ( Inherited condition )

12. Causes Of Colour Vision Deficiency there are three types of cones ( differ on the basis of photoreceptor protein they make) ( Inherited condition ) 1. L-cones sense long wavelength ( red light) 2. M-cones sense medium wavelength ( green light) 3. S-cones sense shorter wavelength ( blue light )

13. Causes Of Colour Vision Deficiency When you see an object light enters your eye and stimulates the cone cells. Your brain interpret the signals from the cone cell and enable you to see the colour of object. They work together enabling us to see whole spectrum of colours. Faulty cones thus are responsible for colour blindness. ( Inherited condition )

14. Causes Of Colour Vision Deficiency Aging. Eye problems, such as glaucoma, macular degeneration, cataracts, or diabetic retinopathy Injury to the eye. Side effects of some medicines. If you have inherited colour blindness your condition will stay the same throughout your life – it won’t get any better or worse. ( Acquired colour blindness )

15. Types Of Colour Vision Deficiency Red-Green deficiency : Blue-Yellow deficiency : There are two main types of CVD : Where people are unable to distinguish certain shades of red and green; it is the most commonly inherited type.. This is a rare condition where it is difficult to distinguish between blue and green, yellow may appear as a pale grey or purple. Protanopes : do not see RED Deuteranopes : do not see GREEN Tritanopia : do not see either YELLOW or BLUE

16. Types Of Colour Vision Deficiency ( Protanopes Type )

17. Types Of Colour Vision Deficiency ( Deuteranopes Type ) Normal Deuteranopes

18. Types Of Colour Vision Deficiency ( Tritanopia Type ) Normal Tritanopia

19. Types Of Colour Vision Deficiency All Type

20. Ishihara’s Test There are many tests available to measure colour vision defects but the most common is the Ishihara Plate test. can test for red/green colour blindness but not blue colour blindness. This is the test most likely to be used for routine colour vision screening in schools or medicals. This test contains 38 plates of circles created by irregular coloured dots in two or more colours.

21. Treatments Of Colour Vision Deficiency There is currently no treatment . Colour filters or contact lenses can be used in some situations to enhance the brightness between some colours. For acquired colour vision deficiency, once the cause has been established and treated, your vision may return to normal.

22. People living with colour blindness: Colour blind people face many difficulties in everyday life Problems can arise in even the most simple of activities including choosing and preparing food, gardening, sport, driving a car and selecting clothing. Colour blind people can also find themselves in trouble because they haven’t been able to pick up a change in someone’s mood by a change in colour of their face

23. Reference WEB MediHelgth ( http://www.webmd.com/eye-health/tc/colorblindness-topic-overview ) Organization Colour blind Awareness ( http://www.colourblindawareness.org/colour-blindness/colour-blindness-experience-it ) Get EYE Smart ( http://www.geteyesmart.org/eyesmart/diseases/colo ) Colblindor ( http://www.colblindor.com/2010/03/02/what-is-colorblindness )

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