colour vision by faslu muhammed

1. OPTOM FASLU MUHAMMED

2. Color vision: Is the capacity of an organism or
machine to distinguish objects based on the
wavelengths or frequencies of the light they
reflect or omit.
Color visionis 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 COLOR VISION

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.

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.

9. COLOR BLINDNESS

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

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

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

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.

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

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

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

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

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

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
tritanopia
 This is the same picture viewed by someone with
Monochromacy which Is full colour blindness

22. THANK YOU