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November 28, 2008


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The Ishihara test has been proven (multiple times) to be the least effective method of diagnosing colour vision issues. All the Ishihara was designed to do is identify when a deficiency is present, not diagnose its severity. However, it became the standard due to its simple nature, and as such, is the be all/end all for colour vision testing, much to the dismay of only mildly deficient individuals such as myself.

Due to the pass/fail nature of the test, someone who is only mildly colour deficient, (to the point they have never experienced problems with colours, such as when identifying traffic lights or matching clothing, etc.) is lumped into the same category as someone who is truly colourblind and cannot distinguish between colours in any way. In fact, the Ishihara test is the only colour vision test I cannot pass. (Explained in further detail below).

As I have already found, it is a disqualifier for many jobs of interest to me, and I am expecting an uphill battle to gain employment in an area relevant to my career goals and interests. The ignorance of colour deficiency is astounding... when discussing my recent job disqualification due to it, a friend said "Well if you're colourblind, how will you identify a suspect's clothing?" To which I replied 'The same as you.' Colour deficiency does not impact any area of my life, nor has it ever, until I went to test for job application. I see and identify colours just as well as anyone else, I just cannot ever see the numbers on the Ishihara test.

In fact, I have seen "colour normal" individuals fail that test. It will trick anyone who is not prepared to take it, and the slightest deviation from the prescribed testing environment will cause failure. In my case, the lighting was insufficient and the test booklet was faded...however, when attempting to file an appeal, it was my word versus that of the facility administering the test, and since I'm not the medical school-trained doctor, there was of course no way I could be right.

Further proof that the Ishihara test is obsolete and inefficient can be evidenced in my case: I am able to pass the FALANT exam, the D15 hue examination, the D100 hue arrangement test, and the RGB anomaloscope; all methods proven to be superior to the Ishihara for diagnosing the severity of colour blindness. By those test results, I am actually considered to be deficiency free. But since Ishihara has become the standard, I'm still considered unable to meet that standard, even when a doctor has said otherwise.

The standard needs to be changed. Thousands of otherwise qualified individuals are having career dreams destroyed in seconds due to this obsolete test. Studies have shown that approximately 35% of those deemed "unfit" for duty based on the Ishihara test could still perform duties without issue if a proper, evidence-based exam would be given. For example, a test mimicking the actual environment that colour vision would be needed in, and having the individual identify colours and patterns in that specific environment; or identifying individual colour cards. Normal colour vision has nothing to do with seeing hidden numbers or squiggles on a piece of paper. Normal colour vision is being able to identify colours of objects in their respective environments when asked to do so. The Ishihara test in no way illustrates how essential colour discrimination would be necessary in any working environment, as colours don't present themselves in real life the way they do on that test.

Unless operational environments start becoming patterned like the Ishihara test plates, I am confident many otherwise "unqualified" colour deficient individuals would be able to perform duties just as well as their colour "normal" counterparts.


I'm curious to know what type of job you applied for that tested for color blindness. I have worked as a Traffic Engineer (a position you'd assume would require perfect color vision) for ten years without significant issues.

I think much of the problem is ignorance about what colorblindness is and is not.

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