Color Vision
Show the child the demonstration card and teach him what each drawing is. Then show him each of the four screening cards and
ask him to tell you which of these drawings he sees. A child with normal color vision will be able to see all four plates. A child with a color deficiency will not be able to see the figures.
(Instructions from: http://www.richmondproducts.com/HRR.htm Accessed 7/23/04.)
Test Administration
The HRR test supports very efficient color deficiency screening. The first four plates are demonstration plates, and used to show the patient how the test works. A camels hair brush is provided for the patient to trace perceived patterns and avoid the deleterious affects of fingerprints. The fourth plate in this demonstration series has no pattern in order to detect for shirkers. The next six plates provide screening by presenting the most difficult yellow, blue, red, and green colors. Success with these plates defines the subject as having normal color vision and completes the test for that person. Subsequent plates appear increasingly bold in color to test for an increasing color deficiency. Proper administration of the color tests requires the use of an illumination of 10 to 60 foot-candles approximating C.I.E. Source C.
Patient Instructions: I am going to show you some colored symbols. Without touching them, how many do you see? What are they? The test is made of these three symbols and they may appear in any of the four corners of the page. Some of them will be harder for you to see, as they may be less strong in color.
Scoring: For subjects with other than normal color vision, diagnosis of type and extent of defect plates 11-24 are used. When the testing is completed, the pattern of checks in each column is examined. Using the test instructions, it is very straightforward to determine from this pattern of correct and incorrect responses the extent of the defect.
Instructions
reprinted from Ishihara Instructions:
http://www.richmondproducts.com/1254%20IshiaraInstructions.htm Accessed 7/23/04)
These plates were not included in your list of equipment and the
instructions have only been included for your knowledge. You may be required to use these plates in
the future and should familiarize yourself with the technique. Do not concern yourself with the terminology
in the explanation of plates. The
interpretation of color deficiencies will be given to you in another class.
The plates are
designed to be appreciated correctly in a room lit adequately by daylight. The introduction of direct sunlight or the use
of electric light may produce some discrepancy in the results because of an
alteration in the appearance of shades of color. When it is convenient only to use electric light, it should be
adjusted as far as possible to resemble the effect of natural daylight. The plates are held 75 cm. from the subject
and tilted so that the plane of the paper is at right angles to the line of
vision. The numerals that are seen on
plates are stated, and each answer should be given without more than three
seconds delay.
It is not necessary in all cases to use the whole series of plates. Plates 12, 13 and 14 may be omitted if the test is designed merely to separate the color defectives from those with normal color appreciation
Explanation of the plates
No. 1.
Any subject, whether with normal or defective color vision will read
correctly the figures 12. This plate
is used mainly for preliminary explanation of the test process to the subjects.
No. 2. Normal subjects will read 8 and those with red-green deficiencies 3.
No. 3. Normal subjects will read 5 and those with red-green deficiencies 2.
No. 4. Normal subjects will read 29 and those with red-green deficiencies 70.
No. 5. Normal subjects will read 74 and those with red-green deficiencies 21.
No.6-7. Correctly decipherable by normal subjects, but illegible or hard to read for those with red-green deficiencies.
No. 8. Clearly 2 for normal subjects but obscure for those with red-green deficiencies.
No. 9. Normal subjects can hardly read it, but most of those with red-green deficiencies see the figure 2 in it.
No. 10. Normal subjects can usually read the figures 16, but most of those with red green deficiencies cannot.
No. 11. In tracing the winding line between the two xs, the normal trace the bluish-green line, but the majority of those with color vision deficiencies are unable to follow the line or follow a line different from the normal one.
No. 12. Normal subjects and those with mild red-green deficiencies see the figures 35 but protanopia and strong protanomalia will read 5 only, and deuteranopia and strong deuteranomalia 3 only.
No. 13. Normal subjects and those with mild red-green deficiencies see the figures 96 but protanopia and strong protanomalia will read 6 only, and deuteranopia and strong deuteranomalia 9 only.
No. 14. In tracing the winding lines between the two xs, the normal trace along the purple and red lines.
In protanopia and strong protanomalia only the purple line is traced,
and in case of mild protanomalia both lines are traced but the purple line is
easier to follow.
In deuteranopia and strong deuteranomalia only the red line is traced and in case of mild deuteranomalia both lines are traced but the red line is easier to follow.