Assessment of inherited colour vision defects in clinical practice

Abstract

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.

Re: Is screening for congenital colour vision deficiency in school students worthwhile?

“…Maybe, they need to do this more than once: when the child has just entered school and later when career choice and driving a car enters their horizons. I draw attention to my paper 5 that provides guidance on the advice that can be given to patients with abnormal colour vision once the severity and type of colour vision deficiency is known.…”

Development of a new test to diagnose and determine the degree of color vision disorders

“…Logo, testes de visão a cores que identifique distúrbios, bem como seu grau de acometimento se fazem cada vez mais necessários. Os testes atuais têm como objetivo classificar o indivíduo como normal ou anormal para a percepção de cores e os diferentes graus da discromatopsia: leve, moderada e forte 14 . Nosso estudo visa validar a eficácia de um novo teste, mais completo, para não apenas identificar indivíduos portadores de discromatopsia, mas também quantificar e graduar seu distúrbio.…”

“…Estudos mostram que ele ainda continua sendo o exame mais eficaz (gold standard) para uma rápida identificação das deficiências congênitas para visão de cores. Porém, esse teste não consegue fornecer uma avaliação quantitativa da deficiência apresentada, pois não possui pranchas para mensuração da gravidade do distúrbio 14 . Além disso, trata-se de um material impresso, ao longo do tempo as pranchas do teste de Ishihara desbotam-se e podem interferir no diagnóstico.…”

Should prospective dental students be screened for colour vision deficits?

“…However, it must be noted that the ability to grade the severity of colour-vision defects with pseudoisochromatic test plates is limited. 12,13 and results from these tests cannot yet be used as a basis for selecting individuals who should be allowed to become dentists. To illustrate, there is large between-individual variability in the perception of white and a very large range of colours are perceived as white by the same observers on different occasions.…”