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

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.     

Using clinical tests of colour vision to predict the ability of colour vision deficient patients to name surface colours

PURPOSE: To determine the predictive power of commonly used tests for abnormal colour vision to identify patients who can or cannot name surface colours without error. METHODS: The colour vision of 99 subjects with colour vision deficiency (CVD) was assessed using the Ishihara, the Richmond HRR (2002), the Farnsworth D15, the Medmont C100 and the Nagel anomaloscope. They named 10 surface colours (red, orange, brown, yellow, green, blue, purple, white, grey and black), which were presented in two shapes (lines and dots) and three sizes. The surface colours were also named by an age-matched group of 20 subjects with normal colour vision. The performance of the clinical tests to predict the CVD subjects who made no colour naming errors and those who made errors is expressed in terms of the predictive value of a pass P((P)) and the predictive value of a fail P((F)). RESULTS: The P((P)) values of the tests were between 0.59 and 0.70 and P((F)) values were between 0.77 and 1.00. CONCLUSIONS: A 'mild' classification with the Richmond HRR test, especially if no more than two errors are made on the HRR diagnostic plates, identifies patients with abnormal colour vision who are able to name surface colour codes without error or only the occasional error. A pass of the Farnsworth D15 test identifies patients who will make no or few (up to 6%) errors with a 10 colour code, but who will be able to name the colours of a seven colour code that does not include orange, brown and purple. If protans are excluded, the predictive value for a pass P((P)) for the Farnsworth D15 is improved from 0.59 to 0.70. The anomaloscope is not an especially good predictor of those who can recognise surface colour codes. However, an anomaloscope range >35 units identifies those who have difficulty in recognising surface colour codes, as does a fail at the Farnsworth D15 test.     

Jan Lovie‐Kitchin

Background: Colour vision deficiency (CVD) has a high prevalence and is often a handicap in everyday life. Those who have CVD will be better able to adapt and make more informed career choices, if they know about their deficiency. The fact that from 20 to 30 per cent of adults with abnormal colour vision do not know they have CVD suggests that colour vision is not tested as often as it should be. This may be because of practitioner uncertainty about which tests to use, how to interpret them and the advice that should be given to patients on the basis of the results. The purpose of this paper is to recommend tests for primary care assessment of colour vision and provide guidance on the advice that can be given to patients with CVD. Methods: The literature on colour vision tests and the relationship between the results of the tests and performance at practical colour tasks was reviewed. Results: The colour vision tests that are most suitable for primary care clinical practice are the Ishihara test, the Richmond HRR 4th edition 2002 test, the Medmont C‐100 test and the Farnsworth D15 test. These tests are quick to administer, give clear results and are easy to interpret. Tables are provided summarising how these tests should be interpreted, the advice that can be given to CVD patients on basis of the test results, and the occupations in which CVD is a handicap. Conclusion: Optometrists should test the colour vision of all new patients with the Ishihara and Richmond HRR (2002) tests. Those shown to have CVD should be assessed with the Medmont C‐100 test and the Farnsworth D15 test and given appropriate advice based on the test results.     

Does the Farnsworth D15 test predict the ability to name colours?

Background: The Farnsworth D15 test is designed to categorise colour vision deficiency as severe or moderate. The level of difficulty of the test was set so that those who passed it should be able to recognise surface colour codes, such as those used for electrical wiring. The test is widely used to provide advice to patients with abnormal colour vision and is often used for occupational selection when reliable recognition of surface colour codes is required. However, there has been only one previous study of the correlation between performance at the D15 test and the naming of surface colour codes and there has been no study of whether a person who passes the D15 can reliably name surface colours. Methods: One hundred and two people aged 11 to 65 years with abnormal colour vision were recruited from consecutively presenting optometric patients and were asked to name the colours of fabric, paint and cotton thread samples. There were 10 colours in each class of material and the samples were presented in a large (five to 10 degree angular subtense) and small size (2.5 deg and a single thread). The errors made were compared to those made by an age‐matched control group of equal size with normal colour vision. Results: The correlations between the Farnsworth D15 colour confusion index and colour naming errors were 0.62 for the large stimuli and 0.73 for the small stimuli. Its sensitivity and specificity identifymg those who made more errors than the worst performing colour normal person were 0.80 and 0.69 (large stimuli) and 0.75 and 0.71 (small stimuli). A Nagel anomaloscope range of less than 35 scale units provides essentially the same sensitivity and specificity. Conclusions: About 40 per cent of those with abnormal colour vision can name the main colours correctly under good visibility conditions. The D15 test is an imperfect predictor of those who can name surface colour codes correctly but it does provide useful information for general counselling. It is not suitable as a single test for occupational selection because it will pass 20 per cent who cannot name surface colours correctly and fail 30 per cent who can. In occupations in which recognition of surface colour codes is of critical importance, it may be best not to select people with abnormal colour vision because of the lack of a colour vision test that is a perfect predictor of the ability to recognise surface colours.     

Validation of the Holmes - Wright lanterns for testing colour vision

The recently introduced Holmes - Wright Type A and Type B lanterns and the Farnsworth lantern were administered to 100 observers with normal colour vision and 100 observers with defective colour vision. With the fail criteria adopted, all normals passed the Holmes - Wright Type A lantern and with one exception all normals passed the Farnsworth lantern. However, 8% of normals failed the more difficult Holmes - Wright Type B lantern. It is noted that the normals who fail this lantern test appear to do so not because of poor colour discrimination but because the coloured stimuli presented by the lantern have a point brilliance close to the average chromatic threshold. About one-third of the colour vision defective group passed the Farnsworth lantern and between 14 and 17% passed the Holmes - Wright Type A lantern depending on the test procedure used. Only two mild deuteranomals in the sample of 100 colour abnormal observers succeeded in passing the Holmes - Wright Type B lantern. Dichromats and severe anomalous trichromats fail all three lanterns so that those who pass are all mild anomalous trichromats. A significant proportion of protanomals pass the Farnsworth lantern and some protanomals pass the Holmes - Wright Type A lantern despite their reduced sensitivity to red light and correspondingly reduced signal range for red signals.     

Abnormal colour vision is a handicap to playing cricket but not an insurmountable one

Background: Two studies have reported that abnormal colour vision is under‐represented among cricketers, presumably because cricketers with abnormal colour vision have difficulty seeing the red ball against the green grass of the cricket field and the green foliage around it. We have previously reported on the difficulties of five cricketers with abnormal colour vision but we have also reported that one of Australia’s finest cricketers was a protanope. This survey was undertaken to confirm the under‐representation of abnormal colour vision among cricketers and to ascertain whether those playing tend to be (1) those with a mild colour vision deficiency, (2) bowlers rather than batsman and (3) prefer to field close to the batsman rather than in the outfield. Methods: The colour vision of 293 members of seven Melbourne Premier cricket clubs was tested using the Ishihara test. Those who failed were examined further to confirm their abnormal colour vision, to assess its severity with the Farnsworth D15 test and to classify it as either protan or deutan using the Medmont C100 test. A questionnaire about cricketing ability and problems playing cricket was administered. Results: Twenty‐six (8.9 per cent) of the cricketers had abnormal colour vision, of whom six played in the First Grade (6.7 per cent of First Grade players). The proportion of cricketers with a severe deficiency was significantly less than expected for the First Grade players. There were only two protans. Bowlers were not over‐represented among the colour vision defective cricketers but those preferring to field close to the batsman were significantly over‐represented. Conclusion: Abnormal colour vision is a modest handicap to playing cricket, especially at the higher levels of the game. It may impede batting and the ability to field in the outfield.     

Evaluation of an updated HRR color vision test

The HRR pseudoisochromatic plate (pip) test was originally designed as a screening and diagnostic test for color vision deficiencies. The original HRR test is now long out of print. We evaluate here the new 4th edition of the HRR test, produced in 2002 by Richmond Products. The 2002 edition was compared to the original 1955 edition for a group of subjects with normal color vision and a group who had been previously diagnosed as having color vision deficiencies. The color deficient subjects spanned the range of severity among people with red-green deficiencies except for one individual who had a mild congenital tritan deficiency. The new test compared favorably with the original and in at least two areas, outperformed it. Among subjects with deutan defects the classification of severity correlated better with the anomaloscope results than the original; all the subjects who were classified as dichromats on the anomaloscope were rated as "severe" on the new HRR, while those diagnosed as anomalous trichromats were rated as mild or medium on the new test. Among those with moderate and severe defects the new test was highly accurate in correctly categorizing subjects as protan or deutan. In addition, a mild tritan subject made a tritan error on the new test whereas he was misdiagnosed as normal on the original.     

The ChromaGen contact lens system: colour vision test results and subjective responses

The ChromaGen lens system is designed to enhance colour perception in colour vision deficiency (CVD). To investigate its efficacy, 14 CVD subjects were prescribed ChromaGen contact lenses. Colour vision tests (Ishihara, Farnsworth Munsell D-15, Farnsworth Lantern) were administered at baseline, lens dispensing, and after a 2-week lens-wearing trial during which subjective responses were recorded daily using visual analogue scales. ChromaGen lenses significantly reduced ishihara error rates (p < 0.001; ANOVA), particularly for deutan subjects. There was also a significant reduction in errors (p < 0.005) on the D-15 test. Conversely, lens wear had no significant effect on Farnsworth Lantern test performance. Subjectively, subjects reported enhanced colour perception, but poor vision in dim light. Judgement of distance and motion were only slightly affected. We conclude that ChromaGen lenses may enhance subjective colour experience and assist in certain colour-related tasks, but are not indicated as an aid for CVD in occupations with colour vision-related restrictions.     

Technical Note: The effect of refractive blur on colour vision evaluated using the Cambridge Colour Test, the Ishihara Pseudoisochromatic Plates and the Farnsworth Munsell 100 Hue Test

The results of a prospective study examining the effect of refractive blur on colour vision performance in normal subjects measured with three different colour vision tests are reported. The Farnsworth Munsell 100 Hue (FM100) and Cambridge Colour Test (CCT) results were significantly affected at +6 D of spherical refractive blur, whereas those from the Ishihara Pseudoisochromatic Plate (IPP) test were not. In a clinical setting, correction of refractive error up to 3 D for colour vision testing with these tests may not be required. Poor colour vision should not be attributed solely to refractive causes of poor visual acuity (Snellen equivalent: >6/36). Fastest test times were achieved using IPP, followed by CCT.     

Pass rates for the Farnsworth D15 colour vision test.

INTRODUCTION: The Farnsworth D15 test (D15) is used worldwide to select applicants for employment in occupations which require good colour vision. People with slight colour deficiency are intended to pass the D15 and people with significant (moderate/severe) colour deficiency to fail. METHODS: Pass rates were determined for 710 adult males with red-green colour deficiency using three different pass criteria in general use. RESULTS: Forty-six per cent of subjects were successful when the pass criterion was a circular results diagram (one single transformation of adjacent hues was accepted as a pass), 53% passed when one red-green isochromatic error was allowed and 60% passed when two red-green isochromatic errors were permitted. The pass rate for 200 dichromats was 1.5% on a circular diagram, 3% on one red-green error and 6% on two red-green errors. Protans made fewer errors than deutans and more protans than deutans were successful when either one or two red-green crossings were permitted as a pass. CONCLUSION: A circular results diagram is the preferred pass criterion. This criterion most nearly fulfils the aim of the test to fail all dichromats and people with significant protanomalous and deuteranomalous trichromatism. A circular diagram is also easy to interpret consistently. Re-examination is recommended if there are only one or two red-green isochromatic error lines across the results diagram. This gives individuals with borderline slight/moderate colour deficiency an opportunity to pass at the second attempt.     

Ocular side effects of phenothiazines

It has been shown that prolonged usage of phenothiazine drugs causes tissue changes in the eye. Such changes were evaluated in 19 long-term psychiatric patients who had taken phenothiazines over periods ranging from five to 32 years to assess whether decreased contrast sensitivity function and colour vision anomalies could be used as indicators of ocular tissue change. Using Vistech gratings, contrast sensitivity was found to be below normal at 6,12 and 18 cycles per degree in 45 per cent, 16 per cent and 39 per cent of the eyes respectively. The Farnsworth Dichotomous Panel D15 test revealed colour vision anomalies in more than half the eyes. However, linear regression analysis showed no systematic relationship between the results of either test and the degree of ocular tissue changes observed.     

Quantitative scoring of panel tests for assessment of colour vision in age related maculopathy

Using the Farnsworth dichotomous D15 test and the Farnsworth-Munsell 100-hue test, Bowman compared the colour discrimination of subjects having age related maculopathy to that of age matched normals. In this paper a quantitative assessment of Bowman's results was obtained using the colour difference vector analysis of Vingrys and King-Smith. The assessment indicates that there is selective blue-yellow loss in age related maculopathy and that the FM 100-hue test is more useful than the D15 test in distinguishing between normal subjects and those with early age related maculopathy. We suggest that the vector method of analysis is particularly useful in clinical trials and in monitoring changes of colour vision over time.     

Who fails lantern tests?

A battery of clinical colour vision tests was given to a group of 100 observers with abnormal colour vision who were also tested on the Farnsworth lantern and the Holmes-Wright lanterns types A and B. It was found that clinical colour vision tests are imperfect predictors of lantern test performance. However, observers classified as having a ‘severe’ colour vision defect were found to fail the lantern tests but only one half to two-thirds of those who fail the lantern tests can be identified in this way. It is not possible to identify with certainty any of the people likely to pass the lantern tests: about one-third to two-thirds of observers classified as being mildly affected fail the lantern tests. The Farnsworth D-15 and City University tests were found to be the best predictors of lantern test performance but other tests such as the Nagel anomaloscope, the H-16, L'Anthony's desaturated test can also be used. The lack of a strong correlation between clinical tests and the recognition of the small coloured stimuli presented by the lantern tests suggests that clinical tests do not test the same aspect of colour vision that is important to the recognition of signal lights. For this reason lantern tests should be retained for occupational testing of colour vision.     

Categorical color naming of surface color codes by people with abnormal color vision.

PURPOSE: Past investigations of the ability of people with color vision deficiency (CVD) to name the colors of surface colors have been occupation-specific. This study was undertaken as a more generalized investigation to explore particularly the effects of stimulus size and shape. METHODS: One hundred CVD observers and 20 color vision normal (CVN) subjects named the colors of two sets of surface colors, each set presenting the same 10 colors (red, orange, brown, yellow, green, blue, purple, white, gray, black). One set presented dot stimuli in three sizes (2.4 degrees , 1.0 degrees , 0.27 degrees ) and the other line stimuli with three widths (0.50 degrees , 0.27 degrees , 0.14 degrees ). Color vision was diagnosed using the Ishihara test, the Farnsworth D15 test, the Medmont C100, and the Nagel anomaloscope. RESULTS: All CVN subjects and 37% of CVD subjects made no errors. Type of CVD and stimulus size were significant factors for probability of error and the effect of stimulus size is best described by 1/area. There were significant interactions between CVD type and 1/area and between shape and 1/area. Deuteranomals who passed the Farnsworth D15 test made significantly fewer errors than all other CVD types and 70% made no errors. Their common errors were to confuse red, orange, and brown. Protanomals who passed the Farnsworth D15 test made fewer errors than dichromats. CONCLUSIONS: Mild deuteranomals will make very few errors with a seven-color code that omits orange, brown, and purple and will make very few errors (approximately 0.3%) with a 10-color code when the stimuli are reasonably large (area >20 mm).     

Effects of Contrast Sensitivity on Colour Vision Testing

This study analyses how contrast sensitivity loss affects colour vision (CV) testing. Eleven participants were scored while cycling through randomly arranged pictures of CV tests with varying levels of contrast changes applied. Hardy-Rand-Rittler (HRR) scores declined significantly at each successive decrease in contrast level after the highest setting (p < 0.004). HRR scores were also lower than those for Ishihara and Farnsworth D-15 tests at two contrast settings (p < 0.01). Contrast changes had the greatest impact on HRR scores, indicating that this test may not be an accurate reflection of CV in patients with contrast sensitivity loss.     

Identification of red–green colour deficiency: sensitivity of the Ishihara and American Optical Company (Hard,Rand and Rittler) pseudo‐isochromatic plates to identify slight anomalous trichromatism

Screening sensitivity, based on a specific number of errors, of the Ishihara plates and of the American Optical Company (Hardy, Rand and Rittler) plates (HRR plates) was determined by reviewing data obtained for 486 male anomalous trichromats identified and classified with the Nagel anomaloscope. Data were obtained for the 16 screening plates, with Transformation and Vanishing numeral designs, of the 38 plate Ishihara test, and for the four red–green screening plates (with six Vanishing designs) of the HRR test. Sensitivity of the Ishihara plates was found to be 97.7% on 4 errors and 98.4% on 3 errors. Only anomalous trichromats with slight deficiency, according to the anomaloscope matching range, made 8 errors or fewer. One screening error, a single missed figure, is normally allowed as a pass on the HRR test and 3 errors is often recommended as the fail criterion to eliminate false positive results. Twenty‐three subjects made no error on the HRR screening plates and 12 subjects made a single error (35 anomalous trichromats). Screening sensitivity was therefore 92.8% using 2 errors as the fail criterion. Screening sensitivity was reduced to 87% when 3 errors was the fail criterion, and some deuteranomalous trichromats with moderate deficiency, according to the anomaloscope matching range, were not identified. Individuals who make a maximum of 2 errors on the HRR test, or on the Richmond HRR 4th Edition, should be re‐examined with the Ishihara plates to determine their colour vision status. The present review confirms that the Ishihara test is a very sensitive screening test and identifies people with slight anomalous trichromatism. The HRR test is unsatisfactory for screening and should not be chosen solely for this purpose.     

Red light increment threshold as a measure of deficient color vision.

PURPOSE: People with deficient red/green color vision have both poor color discrimination and are also insensitive to colored lights, especially red, in an increment threshold situation. In this study we compare detection thresholds for a long wavelength increment to two standard color discrimination tests. METHODS: Forty-five color normal subjects and 19 color-deficient subjects (CDs) (12 deutans, 4 protans, and 3 unclassified) were tested with the Hardy-Rand-Rittler (HRR) plate test (4th edition), Farnsworth D-15 arrangement test and a long wavelength increment threshold test, i.e., the red test. RESULTS: All CDs were less sensitive to the red increment than any of the normal subjects. The red test identified all CDs. There were no significant correlations between the red test results and the HRR test or the Farnsworth D-15 test. CONCLUSIONS: The red test measures red light increment threshold, a characteristic of color vision not assessed by conventional tests of color vision which are based upon measuring loss of color discrimination. All CD observers have raised red light increment thresholds and the test clearly differentiates CD observers from those with normal color vision.     

Colour vision screening in glaucoma: the Tritan Album and other simple tests

Results from simple colour vision tests used for the detection of (he Type III colour vision deficiency in glaucoma and ocular hypertension are presented. We assessed 49 patients with primary open angle glaucoma. 16 ocular hypertensives, 54 age matched normals and 50 young normal observers using six established tests and the recently introduced Tritan Album. This lest was introduced specifically for acquired colour vision deficiencies. Results show in general that individual tests have low sensitivity and poor screening efficiency. The best screening efficiency was achieved by the City University Colour Vision Test and the AO HRR plate test, no acquired tritan defects were identified by the Farnsworth F2 plate, and the Tritan Album had very low sensitivity (the lowest excluding the F2 plate). Best results were obtained from a combination of City University and HRR test scores and this combination could provide useful additional data on colour vision in a glaucoma screening programme.     

Comparison of visual function following implantation of Acrysof Natural intraocular lenses with conventional intraocular lenses

BACKGROUND: Recently an intraocular lens (IOL) has been introduced which blocks blue light. As blocking blue light may be to the patient's detriment, this study was designed to evaluate visual function following implantation of a blue-blocking (Acrysof Natural) IOL. METHODS: Patients were recruited for this non-randomized controlled interventional study, from those attending a private rural ophthalmology clinic for cataract surgery (n = 93). Only those who had previously had a conventional IOL implanted into one eye were offered an Acrysof Natural IOL for the second eye. Postoperatively patients underwent refracted Snellen visual acuity, contrast sensitivity using a CSV-1000E instrument and colour vision testing using a Farnsworth D-15 test, with a subset (n = 20) undergoing a Farnsworth-Munsell 100-Hue test. Results were then compared between eyes. Finally, a subset (n = 63) completed a survey designed to assess the subjective impact of the Acrysof Natural IOL. RESULTS: There were no statistically significant differences between eyes implanted with conventional IOLs compared with Acrysof Natural IOLs for visual acuity (t = 0.57; P = 0.57), contrast sensitivity (t = 0.43; P = 0.67 for 3 cycles per degree [cpd], t = 0.56; P = 0.58 for 6 cpd, t = 0.09; P = 0.93 for 12 cpd and t = 0.16; P = 0.87 for 18 cpd) or colour vision with the Farnsworth D-15 (Chi(2) = 0.38; P = 0.55) or the Farnsworth-Munsell 100-Hue test t = 0.34; P = 0.74). Most subjects reported that they could not tell a difference between the two IOLs subjectively or that any difference experienced was not significant. CONCLUSION: Our sample did not show any significant differences between eyes implanted with conventional IOLs and the Acrysof Natural IOL. We would suggest that the Acrysof Natural IOL may be used without any significant difference in visual function.     

Clinical use of the American Optical Company (Hardy, Rand and Rittler) pseudoisochromatic plates for red-green colour deficiency

The efficiency of the American Optical Company (Hardy, Rand and Rittler) (HRR) plates for screening, grading and classifying red-green colour deficiency was examined for 401 mate colour deficient subjects previously identified and diagnosed with the Nagel anomaloscope. There were 83 protanopes, 30 protanomalous trichromats, 96 deuteranopes and 192 deuteranomalous trichromats. Screening sensitivity was found to be 100% for dichromats and 96.4% for anomalous trichromats based on one screening error (35 subjects, including 7 dichromats, were identified by a single error). Thirty subjects (13.5%) made errors on screening plates only and were identified as having minimal colour deficiency. The HRR grading system did not distinguish dichromats and anomalous trichromats; 54% of dichromats were graded as having moderate rather than severe colour deficiency. Protan/deutan classification was correct for 95% of subjects who failed grading plates. HRR grades for anomalous trichromats were compared with the anomaloscope matching range and with pass or fail of the D15 test. The results show that only two rather than four grading categories can be distinguished by the HRR plates and that both the D15 and the HRR plates are needed in a vocational test battery to establish the severity of colour deficiency.