Color Vision Deficiency and Ishihara's Test

Color vision deficiency's causes, types, and Ishihara's test procedure.

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1. Colour Vision Deficiency
Presented by :
Optometrist (intern) Asma Al-Jroudi
Saudi Arabia, Riyadh, King Abdulaziz University Hospital
30 Dec 14

2. •What Is Color Vision Deficiency?
•Causes Of Color Vision Deficiency
•Types Of Color Vision Deficiency
•Tretments Of Color Vision Deficiency
•Ishihara’s Test
•Conclousion

3. What is Colour Blindness?
•Color blindness, or color vision deficiency, is the
inability or decreased ability to see color, or
perceive color differences, under normal lighting
conditions.
•This condition results from an absence ofcolor-
sensitive pigment in the cone cells of the retina,
the nerve layer at the back of the eye.

4. What is Colour Blindness?
•Cones are the coulored 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.

5. Causes of Color Blindness
•Genetic:
Many more men are affected than women.
•Acquired :
Chronic illness, Accidents, Medications and Age.

6. There are two main types of CVD:
•Red-Green deficiency
Where people are unable to distinguish certain
shades of red and green; it is the most commonly
inherited type..
•Blue-Yellow deficiency
This is a rare condition where it is difficult to
distinguish between blue and green, yellow may
appear as a pale grey or purple.

7. Protanopes: do not see RED
Deutranopes: do not seeGREEN
Tritanopes: do not see either YELLOWorBLUE

9. •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.
Treatment

10. Treatment
•Genetherapy
September 2009, the journal Naturereported
that researchers at the University of Washington
and University of Floridawere able to give
trichromatic vision to squirrel monkeys, which
normally have only dichromatic vision, using gene
therapy.

11. Ishihara’s test

12. Ishihara’s test
•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.
•Contains 24 plates of circles created by irregular
coloured dots in two or more colours.

13. Four Different Types of Plates
1.Vanishing design:
Individuals with normal colour vision could
recognize the figure.
2. Transformation design:
Individuals with colour vision defect should see a
different figure from individuals with normal
color vision.

14. Four Different Types of Plates
3. Hidden digit design:
Only individuals with colour vision defect could
recognize the figure.
4. Classification design:Intended to determine the
type of color vision defect ( protanopia or
deuteranopia) and the severity of it.

15. Steps & Procedure
1.Obtain the chart in the back of the book
Note: before adminstering this test; you should be
tested first.
2.Explain the procedure to the pt.
3.Ask pt first to read the plates with both eyes
(with a corrective glasses if there is one)
4.Test pt’s monocularly, one eye at a time.
5.Record those frames the pt misses.

16. Implementation of Ishihara’s test
Plates 1-17
each figure would be recognized within 3 sec or
less.

17. Plates 1-17
1
st
plate=12
normal and colour vision deficiencies people will
read it 12

18. Plates 1-17
2
nd
=8 3
rd
=29
•Red-green deficiency would read it as:
2
nd
plates=3 , 3
rd
plate= 70
•Those with total colour blindness cannot read any
figures.

19. Plates 1-17
4
th
= 5 5
th
= 3 6
th
= 15 7
th
= 74
•Red-Green deficiency will read it as :
4
th
=2 , 5
th
= 5, 6
th
=17, 7
th
=21
•Those with total color blindness cannot read any
figures

20. Plates 1-17
•8
th
=6 ,9
th
=45 ,10
th
=5 , 11
th
=7 ,12
th
=16 ,13
th
=73
•Majority of thoes with CVD can not read them or
read them incorrectly.

21. Plates 1-17
14
th
& 15
th
plates
•Normal and total colour blindness people can not read
any numeral.
•Only thoes with Red-Green deficiency can read them
as: 14
th
= 5 ,15
th
=45

22. Plates 1-17
16
th
=26 17
th
=42
•protanopic would read it as:
16
th
=6, 17
th
=2
•Deutaneropic would read it as:
16
th
=2 , 17
th
=4

23. Plate no. 18
•In tracing the lines between the two X’s, the
normal trace along purpule and red lines.
•In protanopiaand strong protanomalia Purple
line is traced.
•In deutaneropiaand strong deutanomalia Red
line is traced

24. Plate no.19
•Majority of normal and thoes with total colour
blindness are unable to follow the line.
•In tracing the line between the two X’s majority
of thoes with Red-Green deficiencies trace along
the line.

25. Plate no.20
•Normal will trace the bluish-green line.
•The majority of thoes with colour vision
deficiencies are unable to follow the line.

26. Plate no. 21
•Normals will trace the orange line.
•The majority of thoes with colour vision
deficiencies are unable to follow the orange line
or will follow a different line.

27. Plate no. 22
•Normals will trace the the line that connects the
bluish-green and yellowish-green lines.
•Red-Green deficiencies will trace line connecting
bluish-green and purple.
•Thoes with total colour blindness can not trace any
line.

28. Plate no.23
•Normals will trace the line connecting purple and
orange
•Red-Green deficiencies will trace line connecting
bluish-green and purple.
•Thoes with total colour blindness can not trace
any line.

29. Plate no. 24
All can trace it easily

30. Analysis The Results
•If 13 (out of 24) or more plates are read normally,
the color vision is regarded as normal.
•If only 9 or less than 9 plates are read normally,
the color vision is regarded as deficient.

31. Conclosion
•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.

32. Any Questions ?