The new Richmond HRR pseudoisochromatic test for colour vision is better than the Ishihara test

Abstract

Aim:The Hardy-Rand-Rittler (HRR) pseudoisochromatic test for colour vision is highly regarded but has long been out of print. Richmond Products produced a new edition in 2002 that has been re-engineered to rectify shortcomings of the original test. This study is a validation trial of the new test using a larger sample and different criteria of evaluation from those of the previously reported validation study. Methods: The Richmond HRR test was given to 100 consecutively presenting patients with abnormal colour vision and 50 patients with normal colour vision. Colour vision was diagnosed using the Ishihara test, the Farnsworth D15 test, the Medmont C-100 test and the Type 1 Nagel anomaloscope. Results: The Richmond HRR test has a sensitivity of 1.00 and a specificity of 0.975 when the criterion for failing is two or more errors with the screening plates. Sensitivity and specificity become 0.98 and 1.0, respectively, when the fail criterion is three or more errors. Those with red-green colour vision deficiency were correctly classified as protan or deutan on 86 per cent of occasions, with 11 per cent unclassified and three per cent incorrectly classified. All those graded as having a 'mild' defect by the Richmond HRR test passed the Farnsworth D15 test and had an anomaloscope range of 30 or less. Not all dichromats were classified as 'strong', which was one of the goals of the re-engineering and those graded as 'medium' and 'strong' included dichromats and those who have a mild colour vision deficiency based on the results of the Farnsworth D15 test and the anomaloscope range. Conclusions:The test is as good as the Ishihara test for detection of the red-green colour vision deficiencies but unlike the Ishihara, also has plates for the detection of the tritan defects. Its classification of protans and deutans is useful but the Medmont C-100 test is better. Those graded as 'mild' by the Richmond HRR test can be regarded as having a mild colour vision defect but a 'medium' or 'strong' grading needs to be interpreted in conjunction with other tests such as the Farnsworth D15 and the anomaloscope. The Richmond HRR test could be the test of choice for clinicians who wish to use a single test for colour vision.

Assessment of inherited colour vision defects in clinical practice

“…The Ishihara test was not the first pseudoisochromatic test of colour vision; the German ophthalmologist Jakob Stilling had devised his test in 1878 but the Ishihara test has proved to have the best sensitivity and specificity of all the pseudoisochromatic tests. specificity 7,9,15,19 and can perform acceptably even when it is given under the wrong illumination. 20 Its only problem is that it is so readily available that those who wish to pass, so they can pass the colour vision standard for an occupation, can obtain a copy and learn the correct answers.…”

“…It does not fulfil these two tasks perfectly 15 but the information provided can be useful ( Table 2).…”

“…It has a sensitivity and specificity almost as good as the Ishihara. 15 It can also detect tritan defects, which the Ishihara does not. This might be thought to be of little importance as inherited tritan defects are rare, having a prevalence of only 1 in 13,000 21 and blue and yellow are not as important in colour codes as are red, green and yellow, however, tritans can encounter occupational b.…”

“…15 It is a test well worth adding to the battery of colour vision tests in private clinical practice. It is available from Richmond Products http://www.richmondproducts.com/ 13396RHRR4thEditionProduct.htm.…”

Coloured filters will not give red-green colour deficient observers normal colour vision

“…Hans morfar er også fargesvak. Ishihara og HRR 2002 benyttes ofte som screeningstester (Bailey, Neitz, Tait, & Neitz, 2004;Cole, Lian, & Lakkis, 2006;Dain, 2004), og det er derfor aktuelt å se hvordan kasusene gjør det på disse testene før og etter tilpasning av ChromaGenfilter/-kontaktlinse. Dersom en person leser faerre enn 10 av 15 plater riktig på Ishihara, er det sannsynlig at han har en rød-grønn fargesynssvakhet.…”