What You Should Know About Testing For Color Vision Deficiency

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"Is there a cure or treatment?" is one of the most frequently asked questions about color vision deficiency. When the answer comes back in the negative, anxiety about failing pre-employment testing for color vision deficiency and the effect this would have on career choice, naturally makes you want to know more about the testing procedures.

Most people with color defects understand that an employer must be sure that a potential employee's color vision is suitable for performing the particular tasks encountered in the employer's industry or business. There is a perception, however, especially among individuals with mild red/green confusion who consider themselves fit for a job but are refused employment, that the testing process is unfair.

They feel that testing has less to do with color discrimination and more to do with discrimination of the color deficient individual. Is this perception a fair one? Well, you could certainly make a case which supports it. Here are some important problems associated with color vision tests.

Some of the most commonly used tests are plate tests (e.g. Ishihara, Dvorine, City University Test) and arrangement tests (e.g. Farnsworth Panel D-15 and FM 100-hue Test).

In plate tests, a symbol comprising colored spots is set in a background of differently colored dots. Colors are chosen specifically to make the symbol invisible to color defective individuals.

Arrangement tests differ from plate tests in that they don't aim to distinguish between normal and color deficient individuals. Instead, a set of colored samples of one hue has to be arranged in sequence and matched from a duplicate group of samples.

The idea is to provide suitable testing of candidates for jobs which require color vision representative of most consumers', such as paint mixing, textile dyeing and papermaking. These tests acknowledge the fact that some people with apparently "normal" color vision have great difficulty with color-matching. This can severely compromise their job performance.

Both plate and arrangement tests have their drawbacks. They use simple pass/fail mechanisms and are not designed for the scaling of performance. This lack of fine tuning, along with the fact that these tests might not predict performance in a real-life situation, are two important disadvantages of these routine testing procedures.

For these reasons, many color deficient individuals feel unjustly treated. Only 1 in 3 of the male population with color deficiency are classified as having the more severe form, leaving two-thirds who are only mildly affected. Many of this group, however, are often excluded from employment for failing a simple screening test which provides only very limited information regarding the type or degree of color vision deficiency.

Mildly affected individuals feel that a battery of tests should be administered when applying for jobs where major color deficiency is not an issue. As there is a spectrum of color deficiency, so there is a need, they say, for flexibility on the part of employers to set more reasonable guidelines for job qualifications.

A recent study bears out their criticism. Over 1000 male candidates applying for jobs in color-critical occupations were given three tests: the Ishihara test and two, less sensitive field tests, the Giles Archer Lantern test and the Electricity Supply Industry wire test.

The findings were very revealing. One hundred candidates failed the Ishihara test, but only 16 failed all three tests. But, and this a very important "but" if you have low grade color deficiency, 77 of the 84 who passed some part of their color perception assessment were offered employment suitable for their color vision ability.

The study's conclusions vindicate the views of many color deficient employees who have worked satisfactorily in occupations that now require color discrimination, but who were hired before the widespread use of color vision testing.

These conclusions also highlight the inappropriateness of using a single screening test and rejecting all candidates who fail it. Additional field tests are widely used in the armed services to salvage applicants who have "acceptable" color vision deficiencies. Excluded from some positions, e.g. pilot and electrician, these applicants can still qualify for others, e.g. health care provider and cryptographer.

The solution, then, seems pretty straightforward: use a practical field assessment wherever possible to test relevant color qualifications. The difficulty is there are no hard-and-fast rules, or even guidelines, to help employers establish color requirements for a specific job.

Some advocate the widespread use of the anomaloscope, which is the most accurate instrument for classifying all color deficiencies and requires the matching of two colored fields in color and brightness. A definitive diagnosis would then be given and, if supplemented by a field test, would allow a mildly affected individual to be offered appropriate employment.

Anomaloscopes are very expensive instruments, however, are very time-consuming to operate and require a high degree of skill and training in their use. They aren't a viable option for most employers.

So, what's the way forward? Given the difficulties associated with the present testing procedures for color vision deficiency, more research is needed to classify and quantify color deficiencies. Further research into the prediction of color recognition and identification in various field conditions seems a priority. This would be of particular benefit to individuals working in occupations that involve a range of duties rather than one easily identified color task.

For you, as an individual, the way forward could include lobbying for the above research to be carried out, trying different doctors or asking for different tests. Perhaps testing at an early age for color deficiency is the best way forward: it could save you a lot of money and disappointment further down the line.
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