Colour blind & RYA/MCA

[st599]

I think the DDA will protect you here. Certainly an employer can't state "normal colour vision required" he must state what he need you to do with that vision and make "reasonable" adjustments to allow you to perform the role with your disability.
In a previous role after years of demanding "normal colour vision" I took on a colour blind person, part of whose role (a small part) was to check power cables, coloured red and green, were the correct way round. My "reasonable adjustment" was simply to put a process in where he and only he got someone to double check. If it were a more significant part of his role a filter would have been a "reasonable adjustment".
Using red green filters would be reasonable in my view for sailing too. Now a commercial endorsement is not the same as being employed, but I think it has the same protection. People think the DDA is all about ramps and enough accessible parking spaces outside tescos to cope if the paralympics rolls into town unannounced, but it is actually far better and more sensible than that!

No, they can definitely require normal colour vision and ask you to take a test, provided colour vision is a requirement for the job. E,g, electricians using the new cable standards.

 

[andygc]

The Isihara is a good screening test, but it does nothing to gage the severity of the defect. The lantern test is a better prctical test. People with a very mild defect will generally pass the lantern test, but fail the Isihara.
There are, however, some colour vision defects that the Isihara does not pick up. Worth thinking about next time you fly on a 747 or board a fast ferry. The captain probably has only passed an Isihara test.

and also

Yes it possible to cheat this test,but what does that achieve?

From the perspective of having some specific professional knowledge about this subject, and apologies for a long posting:

1. The Ishihara plates provide a very effective screening test for red/green colour defects. The test detects protanopia (red blindness), deuteranopia (green blindness), protanomaly (reduced red sensitivity) and deteuranomaly (reduced green sensitivity). It cannot detect a tritan (blue) defect. Tritan defects are rare and of no practical relevance to safe navigation.

2. Lantern tests are practical tests of colour vision safety. That is, can the subject identify and reliably discriminate between red, green and white lights? Some are well-designed in that they use the correct colours, others are less useful because the colours used are not representative of the colours used in the real world (ship or aeroplane).

3. If someone correctly identifies the Ishihara plates under the correct lighting, they have safe red/green colour vision. There is no point whatsoever in testing an aircraft pilot or a fast ferry captain with a lantern if he has passed a properly conducted Ishihara test. There was (may still be) a lantern test used by the Royal Navy for deck officers which used a pinhole light source (graded CP1 as opposed to CP2 from Ishihara), but that has never been considered for merchant service.

4. Lantern tests do not measure the severity of a colour vision defect. Like the Ishihara plates they provide a pass/fail test. Measurement of the severity of a colour vision defect requires more sophisticated tests such as the Farnsworth D-15.

5. It is not possible to cheat a properly conducted Ishihara. If there is any suspicion that the candidate has been able to learn the order in which the plates are usually presented it is easy to shuffle them. (Yes, a very senior RAF officer's son did try that and was caught) The plates have no distinguishing features other than a small number which is hidden by the holding frame.

In many countries there are colour vision standards for drivers, especially commercial drivers (busses taxis etc)

6. But not in the UK. Road safety does not rely on good red/green discrimination. Traffic lights have additional visual clues such as the red light being at the top (except in a few American cities). Brake lights are brighter than tail lights and illuminate only when the brake is applied. There has been a considerable amount of research on this topic, which is why DVLA does not test for colour deficiency. Rail safety, on the other hand, does require good red/green discrimination because the other cues that exist on the road do not exist on the railway.

Since 1999 Dr. Thomas Azman has been using the ColorCorrection System™.

7. They are just coloured lenses. There's nothing new about them. They work by reducing the spectrum of light entering the eye. That also means they reduce the total amount of light entering the eye - a great idea at night.

 

[noelex]

5. It is not possible to cheat a properly conducted Ishihara. If there is any suspicion that the candidate has been able to learn the order in which the plates are usually presented it is easy to shuffle them. (Yes, a very senior RAF officer's son did try that and was caught) The plates have no distinguishing features other than a small number which is hidden by the holding frame.

The Isihara tests are unfortunately easily cheated by many colour defects, but I do not think these would be suitable for general publication. A case in Australia a few years back involved a commercial pilot that was shown to have a severe colour vision defect. He could pass the Isihara by cheating and refused to take any other tests. He won and is still flying 747,s

6.. Traffic lights have additional visual clues such as the red light being at the top (except in a few American cities). Brake lights are brighter than tail lights and illuminate only when the brake is applied.

,
There is lots of research correlating the increased risk of traffic accidents to colour vision defects. Here is one paper available for free online.

http://onlinelibrary.wiley.com/doi/10.1111/j.1444-0938.2002.tb03045.x/pdf

 

[andygc]

The Isihara tests are unfortunately easily cheated by many colour defects, but I do not think these would be suitable for general publication. A case in Australia a few years back involved a commercial pilot that was shown to have a severe colour vision defect. He could pass the Isihara by cheating and refused to take any other tests. He won and is still flying 747,s

Please read what I wrote:

It is not possible to cheat a properly conducted Ishihara.

I am well aware of the colour blind Australian pilot and the subsequent litigation. The case was far more complicated than you suggest.

As for road safety, as I said, there has been a considerable amount of research on this topic. Picking out one paper that shows a theoretical risk hardly provides a convincing argument for restricting some 8% of the male adult population from driving. The DVLA uses medical advisory panels to consider the evidence and come up with recommendations for driver medical standards. The process includes a risk assessment. For colour blindness the conclusion is that no restriction is justified on grounds of road safety. It is entirely possible that the circumstances in other countries may lead to a different conclusion, but as I live and drive in the UK that is of no great concern to me.

 

[noelex]

Please read what I wrote:
.

5. It is not possible to cheat a properly conducted Ishihara. If there is any suspicion that the candidate has been able to learn the order in which the plates are usually presented it is easy to shuffle them. (Yes, a very senior RAF officer's son did try that and was caught) The plates have no distinguishing features other than a small number which is hidden by the holding frame.

Yes I did read what you wrote.
Presenting the Isihara in random order with the correct lighting etc does not prevent cheating the test. If you are testing people in a professional capacity you should be aware of this.

 

[andygc]

Again

It is not possible to cheat a properly conducted Ishihara

Oh God, I give up.

 

[noelex]

I will PM you one easy and foolproof method, I do not think it is wise to publish this on an open forum, but it sounds like you are professionally involved in using these tests I think you should be aware how easy it is to cheat on an Isihara.

 

[alan_d]

Again

It is not possible to cheat a properly conducted Ishihara

Oh God, I give up.

I don't know if you are right or not, but restating your opinion more emphatically doesn't really advance the discussion.