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.
They usually can pass the FAA color light gun test, even if they have not met. American Optical Company (AOC) 1965 edition; AOC-HRR, 2nd edition. The test plates to be used for each of the approved pseudoisochromatic tests are: Test Edition Plates AOC 1965 1/15 AOC-HRR 2nd 1/11 Dvorine 2nd 1/15 Guide for Aviation Medical Examiners AOC test results are considered to be more an indicator of the biological growth potential.
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. The HRR pseudoisochromatic test was developed by Hardy, Rand and Rittler, and was first published by the American Optical Company in 1955. It has been much loved by the cognoscenti of colour vision because it included plates to detect tritan colour vision deficiency, as well as the protan and deutan deficiencies and had a carefully designed set of plates to differentiate protan, deutan and tritan deficiencies and grade their severity. The HRR provided the clinician with more information than the Ishihara in a test that was just as easy to administer.
The Ishihara test, renowned for its high sensitivity and excellent specificity for the detection of protan and deutan deficiencies, has no tritan plates and the number of errors made gives little indication of severity. - Moreover, its four protan‐deutan classification plates are not very reliable., A second edition of the HRR test was published in 1957, using material from the first print run but with a rearrangement of the order of the plates. No further editions were published by the American Optical Company and the test has not been available for many years. Richmond Products, a US‐based manufacturer of ophthalmic equipment, published a replica of the test in 1991 but this was not an exact copy of the original test and it was not well received. On the basis of his colorimetric analysis, Dain concluded that it was ‘a pale imitation of the real thing’. Richmond Products published a further edition in 2002, the colours of which have been carefully re‐engineered with the assistance of Jay and Maureen Neitz and James Bailey.
The re‐engineering of the test has moved the colours nearer to the dichromatic confusion lines and has used a revised deutan copunctal as the origin of the deutan confusion lines based on new knowledge gained since the HRR test was first designed. In addition, the colours of the characters on some plates were desaturated slightly, so that dichromats would be graded as having a severe colour deficiency, which was not always the case in the original HRR test.
Colorimetric analyses of the new HRR test, suggest that it should perform better in differentiating protans and deutans and in grading severity. The design of the HRR test is based on very sound principles. Download driver encore n150 adapter. It comprises 24 plates each displaying either one or two symbols, which can be a cross, a circle or a triangle (). The symbols are constructed of coloured dots on a background of grey dots. The coloured dots have chromaticity co‐ordinates that lie on or close to the protan, deutan or tritan dichromatic confusion loci that pass through the chromaticity co‐ordinates of the grey background colours. The patient is asked to name the shape of each symbol they see and indicate its location, which can be in one of four quadrants of each plate. A plate from the diagnostic series of plates of the Richmond HRR test showing two of the coloured symbols on the background of grey dots.
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