colour vision

colour vision by faslu muhammed

1. C o l o r v i s i o n OPTOM FASLU MUHAMMED

2. C o l o r v i s i o n : Is the capacity of an organism or machine to distinguish objects based on the wavelengths or frequencies of the light they reflect or omit. C o l o r v i s i o n is a function of cones and better appreciated in photopic vision.

3. Hue Is the identification of color. Brightness Is the intensity of color. Saturation Is the purity of a color .

4. theories of C o l o r v i s i o n

5. Also called as YOUNG-HELMHOLTZ THEORY. The existence of three kinds of cones, each containing a different photo pigments and maximally sensitive to one of three primary colors RED, GREEN and BLUE . TRI CHROM ATIC THEORY

6. RED sensitive cone pigment / ERYTHROLABE or long wavelength sensitive (LWS) GREEN sensitive cone pigment / CHLOROLAB or medium wavelength sensitive (MWS) BLUE sensitive cone pigments / CYANOLAB or short wave length sensitive.

7. Therefore, color vision is the consequence of unequal stimulation of the 3 types of cones. In a specific ratio. Example : If you stimulate all 3 types of cones about equally the result is white or no color.

8. By HERING Some colors appear to be mutually exclusive. Red with green Yellow with blue . Opponent color theory

9. C o l o r bli ndn ess

10. An individual with normal color vision is known as TRICHOMATE . In color blindness, faculty to appreciate one or more primary colors is either defective (anomalous) or absent (anopia) It may be congenital or acquired

11. X – linked recessive inherited condition. Affecting males(3-4%) more than females(0.4%) It may be Dyschromatopsia Achromatopsia CONGENITAL COLOUR BLINDNESS

12. Color confusion due to deficiency of mechanism to perceive colors . It can be classified in to :- Anomalous Trichromatism Dichromatism Dyschromatopsia

13. The mechanism to appreciate all the three primary color is present but is defective for one or two of them. Protanomalous :- defective red color appreciation. Deuteranomalous :- defective green color Tritanomalous :- defective blue color Anomalous Trichromatic color vision

14. One of the three primary color is completely absent. such individual are called Dichromate. Protanopia :-complete red color defect Deutreranopia :-complete green color defect. Tritanopia :- complete blue color defect. Dichromatic color vision

15. It is an extremely rare condition. CONE MONOCHROMATISM ROD MONOCHROMATISM Achromatopsia

16. Presence of only one color and thus the person is truly color blind. Visual acuity of 6/12 or better. CONE MONOCHROMATISM

17. Complete or incomplete Total color blindness Day blindness (Visual acuity is about 6/60) Nystagmus Funds is usually normal. ROD MONOCHROMATISM

18. Damage to macula or optic nerve. Associated with a central scotoma or decreased visual acuity. ACQUIRED COLOUR BLINDNESS

19. These are the colours of the rainbow and also what they would look like if you were colour blind This is what a normal person would see as the colours of the rainbow How color is seen?

20. This is the same picture viewed by someone with protanopia. This is the same picture viewed by someone with deuteranopia

21. This is the same picture viewed by someone with t ritanopia This is the same picture viewed by someone with Monochromacy which Is full colour blindness

22. THANK YOU