How to Use this Test:
The original card version of this test (by Dr Shinobu Ishihara) was designed to be carried out in a room adequately lit by daylight. The presence of direct sunlight or artificial light may produce some discrepancy in the results because of some alteration in the appearance of shades of colour. This electronic version may also produce some discrepancies as the images have been optimized for web-based delivery and with a monitor resolution of 800×600 and 256 colour display or greater. The results of this test are not to be considered a valid medical test for color blindness and merely serve to illustrate the tests available. If you have any queries about your own possible color vision deficiencies consult your local GP. Position yourself about 75cm from your monitor so that the colour test image you are looking at is at eye level, read the description of the image and see what you can see!! It is not necessary in all cases to use the entire set of images. In a large scale examination the test can be simplified to 6 tests; test, one of tests 2 or 3, one of tests 4, 5, 6 or 7, one of tests 8 or 9, one of tests 10, 11, 12 or 13 and one of tests 14 or 15.

CARD 1:
Both normal and those with all color vision deficiencies should read the number 12.

CARD 2:
Those with normal color vision should read the number 8. Those with red-green color vision deficiencies should read the number 3. Total color blindness should not be able to read any numeral.

CARD 3:
Normal vision should read the number 29.
Red-green deficiencies should read the number 70.
Total color blindness should not read any numeral

CARD 4:
Normal color vision should read the number 5.
Red-Green color deficiencies should read the number 2.
Total color blindness should not be able toread any numeral.

CARD 5:
Normal color vision should read the number 3.
Red-Green deficiencies should read the number 5.
Total color blindness should not be able to read any numeral.

CARD 6:
Normal color vision should read the number 15.
Red-Green deficiencies should read the number 17.
Total color blindness should not be able to read any numeral.

CARD 7:
Normal color vision should read the number 74.
Red-Green color deficiencies should read the number 21.
Total color blindness should not be able to read any numeral.

CARD 8:
Normal color vision should read the number 6.
The majority of those with color vision deficiencies cannot read this number or will read it incorrectly.

CARD 9:
Normal color vision should read the number 45.
The majority of those with color vision deficiencies cannot read this number or will read it incorrectly.

CARD 10:
Normal color vision should read the number 5.
Those with color vision deficiencies will not read the number or read it incorrectly.

CARD 11:
Normal color vision should read the number 7.
Those with color vision deficiencies will not read this number or read it incorrectly.

CARD 12:
Normal color vision should read the number 16.
Those with color vision deficiencies will not read this number or read it incorrectly.

CARD 13:
Normal color vision will read the number 73.
Those with color vision deficiencies should nor be able to read this number or will read it incorrectly.

CARD 14:
Normal color vision and those with total colour blindness should not be able to read any number.
The majority of those with red-green deficiencies should read the number 5.

CARD 15:
Normal colour vision and those with total color blindness should not be able to read any number.
The majority of those with red-green deficiencies should read the number 45.

CARD 16:
Normal color vision should read the number 26.
In protanopia and strong protanomalia the number 6 is read and in mild protanomalia both numerals are read but the number 6 is clearer than the number 2.
In deuteranopia and strong deuteranomalia only the number 2 is read and in mild deuteranomalia both the number 2 is clearer than the number 6.

CARD17:
Normal colour vision should read the number 42.
In protanopia and strong protanomalia the number 2 is read and in mild protanomalia both numerals are read but the number 2 is clearer than the number 4.
In deuteranopia and strong deuteranomalia only the number 4 is read and in mild deuteranomalia both the number 4 is clearer than the number 2.

CARD 18:
The normal should trace along the purple and red lines between the two X’s.
In protanopia and strong protanomalia only the purple line is traced and in mild protanomalia both lines can be traced but the purple line is easier to follow.
In deuteranopia and strong deuteranomalia only the red line is traced and in mild deuteranomalia both lines are traced but the red line is easier to follow.

CARD 19:
The majority of those with red-green color blindness can trace the winding line between the two X’s.
The majority of those with normal and total color blindness are unable to follow the line.

CARD 20:
Normal will trace the blue-green line between the two X’s.
The majority of those with color vision deficiencies will be unable to follow the line or will follow a line different to the normal one.

CARD 21:
Normal will trace the orange line between the two X’s.
The majority of those with color vision deficiencies will be unable to follow the line or will follow a line different to the normal one.

CARD 22:
Normal should trace the line connecting the blue-green and the yellow-green.
Those with red-green deficiencies trace the line connecting the blue-green and purple.
Those with total color blindness cannot trace any line.

CARD 23:
Normal should trace the line connecting the purple and the orange between the two X’s.
Red-green deficiencies should trace the line connecting the purple and the blue-green.
Total colour blindness and weakness cannot trace any line.

CARD 24:
Both normal and those with color vision deficiencies can trace the winding line between the two X’s.
Source
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