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.
Optometrists and optometric practice staff should adopt measures to minimise the risk of transmission of infection. These include appropriate hand-washing, staff vaccinations, single use instruments/equipment, appropriate disposal of waste, appropriate methods of reprocessing where items are reused, routine employment of standard infection control precautions and application of more rigorous procedures for individuals who are known to be infected or immuno-suppressed. Information provided to patients regarding infection control procedures in topical drug administration, contact lens wear and use of eye make-up are additional considerations for optometrists.
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).
Position the lens on its side, then immerse the entire lens in the selected solution for 25 minutes. Remove the lens from the solution and thoroughly rinse with room temperature water, then dry with a soft, lint-free cloth. APPENDIX Infection control guidelines for optometrists 2007 Lakkis, Lian, Napper and KielyClinical and Experimental Optometry 90
Background : People with abnormal colour vision often report difficulty seeing coloured berries and flowers in foliage, which suggests they will have a diminished capacity for visual search when target objects are marked out by colour. There is very little experimental evidence of the effect of abnormal colour vision on visual search and none relating to search for objects in natural foliage. Method : We showed 79 subjects with abnormal colour vision (seven protanopes, 10 deuteranopes, 16 protanomals and 46 deuteranomals) and 20 subjects with normal colour vision photographs of natural scenes and asked them to locate clumps of red berries, to trace the length of a red string on grass and to name the season depicted in a photograph taken in the Autumn and the same scene photographed in the Summer. Colour vision was assessed using the Ishihara, the Medmont C100, the Farnsworth D15, the Richmond HRR and the Nagel anomaloscope. Results : All the subjects with abnormal colour vision located fewer clumps of red berries than those with normal colour vision. The subjects who failed the Farnsworth D15 performed significantly worse than those who passed but the distribution of scores in the two groups overlaps. The majority of subjects with abnormal colour vision could not trace the full length of the string: only 38 per cent of anomalous trichromats who passed the Farnsworth D15 test and three per cent of those who failed it were able to trace the full length of the string. Fifty-five per cent of those classed as having a mild deficiency by the HRR test could trace the whole string. Most dichromats were unable to identify the Autumn season and those who did may have been assisted by guessing. Most (94 per cent) of those who passed the Farnsworth D15 test and all those classified as having a 'mild' deficiency by the HRR test could identify the season. Conclusions : All people with abnormal colour vision, even those with a very mild deficiency, have some degree of impairment of their ability to see coloured objects in natural surroundings. A pass at the Farnsworth D15 test or a 'mild' classification with the Richmond HRR test identifies those likely to have the least problems with visual search and identification tasks. The results have practical implications for the selection of personnel in occupations that involve visual search in natural terrain.
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.
The emergence of a novel influenza A virus (Influenza A[H1N1]), which has not circulated previously in humans, has led to the first global influenza pandemic in 41 years. Influenza A(H1N1), commonly called ‘swine flu’, is a novel influenza virus made up of porcine, avian and human genes, and preferentially infects younger people. Although Influenza A(H1N1) does not appear to be likely to cause as many fatalities as previous influenza pandemics, attempts to contain it are necessary because people whose health is already compromised through underlying chronic medical conditions are at risk of death if they contract the virus. In addition, pregnant women who become infected are at increased risk of complications. This paper provides figures on the number of cases of Influenza A(H1N1) and deaths associated with this virus in Australia (using World Health Organization and Australian Government figures) and discusses infection control measures that optometrists should put in place for themselves, their staff and their patients, in the event that there is suspicion of Influenza A(H1N1) infection. Measures include isolating those who display symptoms indicative of influenza, use of surgical masks (P2 [N95]) by the infected person, frequent hand‐washing, appropriate cough and sneeze etiquette, disposal of used tissues and rescheduling of non‐urgent appointments for those thought to be infected. Any staff members who need to be closer than one metre to the infected person should also use personal protective equipment (for example, surgical masks, goggles or safety spectacles, gowns and gloves). The current evidence indicates that Influenza A(H1N1) should be treated by optometrists as another type of flu. As with other forms of influenza, following basic infection control guidelines will help reduce the spread of infection in optometric practices and within the community.
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