presentation on color blindness

1. COLOUR
BLINDNESS
Presented by: Meera Qaiser
Presented to: Miss Irum Anjum
Subject: Essentials of genetics
Major: Biotechnology
Semester: 4th

2. WHAT IS COLOUR BLINDNESS?

Color blindness means that you have trouble
seeing red, green, or blue or a mix of these colors.
It’s rare that a person sees no color at all.

Color blindness is also called a color vision
problem.

A color vision problem can change your life.

3. CAUSES OF COLOUR BLINDNESS:
Usually genetic condition.
 Red/Green or Blue colour blindness is passed down
from parents.
 The gene responsible is on X chromosome.
 mutations capable of causing color 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
1.

4. o
Inherited condition maybe due to following…..
o
In our eye there are two types of light sensitive cell
1.
Rods
2.
cones
o
Both found in retina which is a layer at the back of eye
it processes images.
o
The rods are responsible for vision in night as work in
low light condition ( cannot distinguish different
wavelength of light)
o
The cones are responsible for color discrimination

5. CONTINUED
o
there are three types of cones
o
( differ on the basis of photoreceptor protein they
make)
1.
L-cones sense long wavelenght ( red light)
2.
M-cones sense medium wavelength ( green light)
3.
S-cones sense shorter wavelenght ( blue light )

6. 
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 color blindness


7. 2.
Acquired color blindness:

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.

8. TYPES OF COLOUR BLINDNESS
1.
Trichromacy ( three colour vision )
-
Normal colour vision
2.
Anomalous trichomacy ( unusuall three colour vision )
-
See all three primary colour
-
One colour is seen weakly
-
Protanomaly ( l-cone defect ) red weak
-
Deuteranamoly ( M-cone defect ) green weak
-
Tritanomaly ( S-cone defect ) Blue weak

9. 3.
Dichromacy ( two colour vision)
-
See only two of three primary colours
-
One cone is totally disfunctional or absent
-
Protanopia ( l-cone absent )
Detutranopia ( M-cone absent )
Tritanopia ( S-cone absent )
-
4.
-
Rod monochromacy (no cones at all )
Sees no colour only shades of grey

11. INHERITENCE PATTERN
Red-green colour blindness is usually inherited
from parents
 It is passed from mother to son on 23rd
chromosome which is sex chromosome
 Chromosomes are the structure which contains
genes, they contain instructions for the
development of cell tissues organ and if you are
colour blind it means instructions for cone
development are wrong
 It may be missing or less sensitive
 Or pathway from cone to brain is not developed
properly


12. 
For male to be color blind his X chromosome should
have the faulty gene

The female might have both X chromosomes normal
or one X chromosome might have faulty gene but
gene on other chromosome compensates it so the
female is carrier and passes on faulty gene to her
son so he is colorblind

The daughter might be carrier or color blind if her
father is colorblind and mother is the carrier

13. COLOR BLIND MAN NON
COLOR BLIND WOMEN

14. NON COLOR BLIND MAN
COLOR BLIND CARRIER
MOTHER

15. COLOR BLIND MAN COLOR
BLIND CARRIER WOMEN

16. NON COLOUR BLIND MAN
COLOUR BLIND WOMEN

17. DIAGNOSIS
It maybe difficult to detect in children with inherited
colour vsion deficiency as they don’t know whats
wrong with them
 If you have eye test with optometrist he should
check your colour vision as a matter of routine


18. ISHIARAS 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.

19. PLATES FOR ISHIARAS TEST

20. TREATMENT
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.


21. 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


22. REFERENCES

http://www.webmd.com/eye-health/tc/colorblindness-topic-overview

http://www.colourblindawareness.org/colourblindness/colour-blindness-experience-it/

http://www.geteyesmart.org/eyesmart/diseases/colo
r-blindness.cfm

http://www.colblindor.com/2010/03/02/what-is-colorblindness/

23. Thankyou