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Dort
20-10-09, 20:55
Looking for commercial endorsements and/or the more advanced amateur tickets (Coastal to Ocean).

I have a red & green vision deficiency, while I am not completely colour blind. And while sometimes it takes me a while to recognise the colour of a distant buoy or a light, I do fare quite well while navigating. Due to many factors, sometimes seeing it first despite everything, and sometimes just knowing what should be where, I often know what's going on before better-sighted mates do.

Does anyone have experience if RYA/MCA are willing to issue restricted tickets for the 'colour blind' like me, or perhaps even equate practical abilities over the medical exam?

This is embarrassing, never been in trouble (quite the opposite) in practice, .. until reading up what they want.

Dort

andygc
21-10-09, 14:07
There are no colour vision testing requirements for the RYA exams, but if you fail to identify nav lights at night I suppose you would fail.

The formal test is required as part of the medical assessment for the commercial endorsement.Go to the MCA web site and search on "colour vision". You will find various documents. The issue for you is fitness for lookout duties. If you can pass the Holmes Wright B lantern test you would be "fit" and therefore should be able to meet the standard required for a commercial endorsement. I don't know the mechanism for getting the test and the waiver from the MCA, but if you read any relevant documents you should be able to find out.

Why be embarrassed? About 8% of white, male, Europeans and Americans have a significant red/green deficit.

snowleopard
21-10-09, 14:22
When I took the old Board of Trade yachtmaster the exam involved a sight test using coloured lamps in a dark room. Some colour blind people managed to get through because when they used oil lamps the colours showed up as different intensities. I recall one experienced mariner who was completely stuffed when they changed to electric lights.

These days there is no sight test for exams up to Yachtmaster though there is a colour blindness test in the medical required for the commercial endorsement.

I presume you know about the red & green colour filters you can use to distinguish red and green lights. I can't imagine an examiner would fail you if you used a set of these and were able to get the correct readings with them.

For the benefit of anyone who is red/green colour blind and doesn't know about these, you get a pair of red and green filters. When you look at a red light through a green filter you can't see it, likewise a green light can't be seen through a red fillter. You use them by moving the filter back and forth across the light in question. If the light is white or the same colour it shows all the time. When the light is the opposite colour it will wink out as the filter goes in front of it.

A friend with this condition described red and green as 'a dirty shade of yellow'. I imagine it is possible to distinguish between white and yellow lights.

elton
21-10-09, 14:37
In most cases of red/green defficiency, the red/green receptors are tightly concentrated in the centre of the retina rather than being more widely distributed as is the norm. As you may know, many red/green 'defficients' can often discern colour quite accurately by staring at the object directly.

There are products such as ColorView (http://www.color-view.com/) which will enhance red/green differentiation. In fact all you need is a single pink-tinted contact (or spectacle) lens.

flaming
21-10-09, 15:15
I have a friend who had the same issue.

He had a yachtmaster ticket, so I don't think that it restricts you from getting the ticket. But when he wanted to get commercially endorsed he couldn't.

I've never asked him the details, so I don't know the exact reason/test that stopped him, but I do know that he wanted to be commercial but couldn't on account of his eyesight.

KenMcCulloch
21-10-09, 15:46
I think if an examiner realised you had difficulty distinguishing red/green, during your YM practical exam, that might give them pause. There is probably guidance for examiners on this matter.

I do know that when I had a medical for commercial endorsement the doctor conducting the examination was delighted to be able to test my colour vision and field (peripheral) vision, because those were about the only actual medical tests, all the rest was just questions about whether I had ever had a stroke or whatever.

noelex
21-10-09, 17:35
In most cases of red/green defficiency, the red/green receptors are tightly concentrated in the centre of the retina rather than being more widely distributed as is the norm. As you may know, many red/green 'defficients' can often discern colour quite accurately by staring at the object directly.
.
An interesting theory, but I am afraid it bears no resemblance to reality.

andygc
21-10-09, 20:38
There are products such as ColorView (http://www.color-view.com/) which will enhance red/green differentiation. In fact all you need is a single pink-tinted contact (or spectacle) lens.

I have spent a considerable amount of time on looking at colour vision requirements and standards for occupational purposes, mostly in aviation, but also in some other fields. This product is an excellent way of taking money from suckers.

It's really quite simple, you either have adequate red/green discrimination to distinguish between red, green and white lights at night, or you don't. For maritime purposes the Ishihara plates are a screening test - if you can read them you are for practical purposes red/green normal. If you can't read them you need a specific occupational test, which is the Holmes Wright lantern. That uses red and green filters that match the internationally standardised colours for navigation lights. If you can't pass the Holmes Wright lantern test you are unsafe to act as a lookout at night and you will not meet the standard for a commercial endorsement or any other professional watch-keeping certificate.

elton's theory is marvellous, but as noelex suggests, is nonsense. The cones (colour sensitive cells) are wholly concentrated in the centre of the retina. Red/green defects (of which there are two different types) arise (in simple terms) because of either a substantial or complete lack of red or green sensitive cones. Vision in the periphery is mediated by rods which provide monochrome vision.

The colour filters mentioned by snowleopard might work for some people some of the time, but are not a reliable means of discriminating between navigation lights. These filters work by relying on the substantial overlap in the spectral sensitivity of red and green cones. There is overlap with blue, but much less so. Even the best colour filters have some transmission loss. These will not stay in good optical condition for long.

The unreliability arises because the filter will reduce the brightness of the light which is being detected by a cone which is not particularly sensitive to that wavelength. So, for somebody who is red cone deficient, a green light through a green filter is dimmed by the filter, but detected by the green cone. A red light through a red filter is dimmed by the filter, but has to be detected by the overlap sensitivity of a green cone. It needs to be bright to be seen. The approaching red light on the starboard bow will be seen initially as a 'don't know' which disappears when seen through both red and green filters, remaining a 'don't know'. It eventually becomes a dim light seen through a red filter, shortly before the crash alteration of course to give way to a crossing vessel.

Of course, you also have to remember which is the red filter and which the green, because if you are colour deficient you probably can't tell by looking at them, especially in the dark. Strikes me that they are a great idea.

Ariadne
22-10-09, 10:27
For MCA issued tickets you will need to pass the MCA lantern test - a series of red, green, white and yellow lights set at brightness of 6 miles (I think that was what it was when I did mine?).

**This used to have be taken without any reading or eyesight aids.**

Having a letter from your optician to state you had god vision and were not colour blind wasn't accepted, you had to pass their lantern test and it was only valid for 6 months from date of issue (but you didn't have to take it again until you upgraded your ticket. If you fail you used to be able to get referred to an MCA approved optician - at your own cost who could retest you and issue a lantern test certificate.

So get your eyes checked first before you spend.

My advice would be to contact the MCA first about your eyesight concerns and ask them how you should proceed.

chwarae
22-10-09, 19:49
I am red green colour blind and have found the red/green lenses (spelling) to be a great help. My vision other than colur blindness is excellent and don't need to wear wet,steamed up glasses as a number of friends are forced to do on bad nights.I just look upon the lenses as some one with poor eyesight would look upon their spectacles.
I also realise that white steaming lights are normally brighter than red and green lights and play a major part in identifying the course of a craft.
I am also surprised how many red/green colour blind sailors are around.

chwarae
22-10-09, 19:54
I failed to mention that the plastic lenses are shaped differently to enable you to distinguish them by touch at night,thereby protecting your night vision.

carise
23-10-09, 11:38
I have looked into getting commercial endorsement as someone who holds an advanced powerboat certificate and from time to time assists a friend in running a school.

I am red/green colour deficient, and have never had a problem in reality, but am unable to find a legal way to obtain a commercial endorsement, as the test for this is NOT a lantern test (which I can pass), but the good old Ishihara test (ie all those coloured dots and numbers etc)(which I can't pass!!). If you cannot pass Ishihara without coloured lenses then you cannot legally get a full commercial endorsement (although you might be able to get a restricted endorsement eg 'daylight hours only', on appeal).

Having said that, I know of a number of commercially endorsed sailors and motorboaters out there who are red green colour deficient and have very accomodating GPs who appear not to be familiar with this requirement :rolleyes: !!

Have a look at section 5
https://afrmmcanet.mcga.gov.uk/formspublic/MSF4112.pdf

bilbobaggins
23-10-09, 11:54
This is perhaps of far wider significance.

While teaching the RYA's Shorebased Courses - Lights and Shapes - I'd ask a group of 20-24 how many had a colour vision issue. Typically, 5-6 would put up their hands.

I'd also ask who had a diabetes diagnosis, had sleep anoeia, or who had a heart complaint. By that point, typically over half the group had self-identified.

Then I asked if any of them had ever been asked by a skipper if they had any 'medical issues' s/he ought to be aware of before going offshore.

Not once..... not even on sea-school boats.

And how many of those using Commercially-Endorsed RYA qualifications as Cruising ( or other ) Instructors tell their charges of any constraints they may have?

:confused:

carise
23-10-09, 12:01
Good points, well made sir!

If you look at the regulations etc (Link on my previous post) and compare these to some of the less than healthy looking commercially endorsed types out there, it does really raise the question of how robustly the rules are enforced after someone gets their ticket stamped as endorsed!!?


This is perhaps of far wider significance.

While teaching the RYA's Shorebased Courses - Lights and Shapes - I'd ask a group of 20-24 how many had a colour vision issue. Typically, 5-6 would put up their hands.

I'd also ask who had a diabetes diagnosis, had sleep anoeia, or who had a heart complaint. By that point, typically over half the group had self-identified.

Then I asked if any of them had ever been asked by a skipper if they had any 'medical issues' s/he ought to be aware of before going offshore.

Not once..... not even on sea-school boats.

And how many of those using Commercially-Endorsed RYA qualifications as Cruising ( or other ) Instructors tell their charges of any constraints they may have?

:confused:

Elessar
23-10-09, 17:19
I am red/green colour deficient, and have never had a problem in reality, but am unable to find a legal way to obtain a commercial endorsement, as the test for this is NOT a lantern test (which I can pass), but the good old Ishihara test (ie all those coloured dots and numbers etc)(which I can't pass!!). If you cannot pass Ishihara without coloured lenses then you cannot legally get a full commercial endorsement (although you might be able to get a restricted endorsement eg 'daylight hours only', on appeal).


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!

andygc
23-10-09, 19:03
The DDA is based on somebody having a substantial impairment of activities of day to day living which must affect one of the following:

mobility:
manual dexterity;
physical co-ordination;
continence;
ability to lift, carry or otherwise move everyday objects;
speech, hearing or eyesight;
memory or ability to concentrate, learn or understand; or
perception of the risk of physical danger.

The statutory guidance on the interpretation of the Act states:

"It would not be reasonable to regard as having a substantial adverse effect ...
inability to distinguish between red and green."

An employer can state "normal colour vision required" and is not obliged to make any adjustment for somebody who has a colour vision deficit.

Your decision to take somebody on was an example of good employment practice, but was not an adjustment for disability since the person concerned was not "disabled" within the meaning of the Act. As far as identifying coloured cables is concerned filters are most definitely not the answer.

The DDA does not override other statutes. For example, the DVLA discriminates directly against diabetics, epileptics, people with sleep apnoea, people with significant mental illness and people with monocular vision, all of whom are likely to be eligible for the Act's protection. The MCA has statutory authority to set medical standards for seafarers and does so. Again, it discriminates directly. Such discrimination is lawful.

Elessar
24-10-09, 18:08
"It would not be reasonable to regard as having a substantial adverse effect ...
inability to distinguish between red and green."

An employer can state "normal colour vision required" and is not obliged to make any adjustment for somebody who has a colour vision deficit.

Your decision to take somebody on was an example of good employment practice, but was not an adjustment for disability since the person concerned was not "disabled" within the meaning of the Act.
Interesting. My HR department was risk averse but it does look like I was poorly advised.

Dort
25-10-09, 01:16
Thank you all for your comments, I appreciate it.

I know I'll fail Ishihara anyway (even if Colorview etc glasses work, they are banned). I know on the medical form, they explicitly mention Ishihara. I'm going to find a place to do the lantern test anyway, but is even passing it going to help me?

And during the practical test, do RYA/MCA examiners generally emphasize perfection to specific requirements, or more generally managing with the situation?

In other words. I'd be confident if they let me have it my own way and time to produce safe results and exact FIXes, or react to situations, but less so if they just were bombing me with 'what's that light over there 8 miles away'. That's because I have at least limited night sailing training and experience. Thus I already know I'm not the sharpest spotter for a distant sector light, but still eventually can make it out before it becomes important. Sometimes (not often) even faster than those with perfect colour vision, probably either due to being more attentive or just generally being more aware than the rest of where I am and what I need to look for. (Not to brag / dismiss the issue, just to define my case).

Dort

andygc
26-10-09, 17:21
Dort

I wrote to the MCA at the end of last week to ask for clarification on their policy. They have a document on their web site which says that the seafarer's vision test is Ishihara, but another document that describes the use of the lantern test to permit seafarers with a degree of red/green impairment to be assessed fit for lookout duties (which is the issue at point here). I'm interested in the answer from a professional perspective. I'll post the answer here when I get it.

Andy

Dort
28-10-09, 23:31
Dort

I wrote to the MCA at the end of last week to ask for clarification on their policy. They have a document on their web site which says that the seafarer's vision test is Ishihara, but another document that describes the use of the lantern test to permit seafarers with a degree of red/green impairment to be assessed fit for lookout duties (which is the issue at point here). I'm interested in the answer from a professional perspective. I'll post the answer here when I get it.

Andy

Andy, I'd really be grateful for that!

Meanwhile I'm already searching for a place with one of those lantern tests, to see how hard they are in reality. Like seeing the traffic lights a mile afar, or trying to see through a needle hole 6 feet away. Anybody with experiences to describe?

Dort

snowleopard
29-10-09, 07:33
Andy, I'd really be grateful for that!

Meanwhile I'm already searching for a place with one of those lantern tests, to see how hard they are in reality. Like seeing the traffic lights a mile afar, or trying to see through a needle hole 6 feet away. Anybody with experiences to describe?

Dort
I took the test 35 years ago. I recall it was pinpoints of light at a distance of around 10 ft. They weren't very bright so, even with normal vision I wasn't always certain. The white could look a bit coloured, possibly as a result of interference fringes.

The test consisted of a series of pairs of lights. Not too difficult when they were different but a bit more tricky when they were the same and there was nothing to compare with.

andygc
30-10-09, 10:48
Why am I not surprised that the MCA doesn't respond to e-mail enquiries?

I had a bit more time on my hands so I had another search around the MCA website. After reading through pages of medical standards I came to this, which is the definitive statement on colour vision requirements. The relevant document is MSN 1765(M):

COLOUR VISION

Deck officers and ratings - Colour vision should be tested by the approved doctor with Ishihara plates, using the introductory plate, and all the transformation and vanishing plates. Those used should be recorded on the medical report form (ENG 2). Candidates who fail the Ishihara colour plate test may apply to one of the MCA’s nominated Marine Offices listed at Annex C to this MSN, for their colour vision to be re-tested using a Holmes Wright B lantern.

Engineer and radio department personnel should have their colour vision tested by the approved doctor using Ishihara plates (as for deck department). Those who fail the Ishihara test may apply to any registered optician for confirmatory testing using the Farnsworth D15 test or City University test.

In all cases where a follow-up test has been undertaken, a report showing the result must be returned to the approved doctor, on the basis of which he/she will decide whether it is appropriate to fail the candidate or issue a full or restricted medical certificate, reflecting the duties the seafarer will be required to undertake.

Any decision relating to subsequent colour vision testing should be officially recorded by the Marine Office or optometrist and retained by the seafarer with the ENG 1 to avoid the necessity for repeated secondary testing.

Other personnel should be tested for colour vision, where relevant for the duties to be undertaken, using the Ishihara plates.

In other words, if you are red/green deficient and you want a commercial endorsement to your RYA YM certificate you will need to contact one of the nominated Marine Offices to arrange a Holmes Wright lantern test.

They are:

MCA MARINE OFFICES WHERE LANTERN TESTS ARE HELD

1. Aberdeen Marine Office
Marine House
Blaikies Quay
Aberdeen AB11 5EZ Tel: 01224 597900 Fax: 01224 571920

2. Hull Marine Office
Crosskill House
Mill Lane, Beverley
North Humberside HU17 9JB Tel: 01482 866 606 Fax: 01482 869 989

3. Southampton Marine Office
Spring Place
105 Commercial Road
Southampton
SO15 1EG Tel: 023 80329329 Fax: 023 80329351

Ariadne
31-10-09, 09:37
As I remember my MCA Oral exam at Liverpool - I had to produce my ENG1, sight test cert' and all other relevant bits of paper before being allowed to 'sit' the exam.

The exam was a series of questions that covered just about everything you could think of and all sorts of various situations including using models for docking situations. Taking horizontal and vertical sextant angles, demonstrating that you could use various nav aids and explain how you would use the info. Bearing in mind you had already passed all your written papers before going in. Don't know about the RYA, but my MCA examiner held an Extra Masters F.G. with a life time at sea to go with it - he knew his stuff and just wanted to know I did.

No actual practical exam, as you had to have a minimum of two years seatime in a watch keeping capacity to get there, along with testimonials to state you were a sober, upright and reliable character!

When I passed he shook my hand and wished all the best in my career at sea, then got me a cup of coffee to recover!

alant
01-11-09, 14:14
Looking for commercial endorsements and/or the more advanced amateur tickets (Coastal to Ocean).

I have a red & green vision deficiency, while I am not completely colour blind. And while sometimes it takes me a while to recognise the colour of a distant buoy or a light, I do fare quite well while navigating. Due to many factors, sometimes seeing it first despite everything, and sometimes just knowing what should be where, I often know what's going on before better-sighted mates do.

Does anyone have experience if RYA/MCA are willing to issue restricted tickets for the 'colour blind' like me, or perhaps even equate practical abilities over the medical exam?

This is embarrassing, never been in trouble (quite the opposite) in practice, .. until reading up what they want.

Dort


SWMBO, asked a 'logical' question, which was why Red/Green were originally used to distinguish port/starboard etc.

Anyone know?
Was it simply that these were the easiest glass colours to make?

Dort
03-11-09, 21:35
SWMBO, asked a 'logical' question, which was why Red/Green were originally used to distinguish port/starboard etc.

Anyone know?
Was it simply that these were the easiest glass colours to make?

I believe they were chosen rather accidentally by IALA just out of the various colours used around the world to create a uniform standard. Which still doesn't explain why not e.g. blue.

On topic: anyone gotten a daytime only ticket straight off the examination? Without a lengthy chat with the MCA?

jipsey
05-11-09, 07:54
In 2005 I completed a degree in Watersports Studies and Management at Solent Uni with the intention of heading off into the big world to work on super yachts. At the same time I scraped together the money to do my Yachtmaster ticket and all the relevant RYA courses. A couple of weeks before I was due to head off I went to have my ENG1 medical only to fail the ishara test.

I have colourblind family members on both sides of my family, and as a female colourblindness is very rare. I'd had a number of tests using the Ishara test at school and passed all of these but the doctor explained that the test is only true if undertaken under specific lighting conditions (its a while ago now but I think it needs to be under a pure white light, I can pass fine under a normal everyday light bulb), most doctors don't bother with the proper lighting but I'd managed to find a particularly fastidious doctor who was only able to issue my ENG1 with restrictions.

The doctor advised me to contact the MCA to appeal this decision and so in April 2006, when I was next in the UK, I went to the MCA headquarters in Southampton for the lantern test. This did not cost me anything (I still have my 'free certificate' to say that I am indeed colourblind!). I also went up to see specialists at the Moorfield eye hospital in London to check that it wasn't a case that my colour vision was deteriorating, but it would appear that it is a condition that I have always had, but it just wasn't picked up because I can just about complete the ishara plates under a normal bulb. I spent over 2 years working afloat as a deckhand but came back to the UK to a 'normal job' after being advised by the RYA and MCA that any comercial endorsement would be severly limited (who in their right mind is going to employ a mate/captain who needs an equally qualified person with good colourvision to stand next to them at night?). The frustrating thing is that having good sight otherwise I was usually able to see lights, and often identify reds/greens, at a further distance than others onboard, but that doesn't count!

I'm currently undertaking a total career change and would strongly advise anyone who would like a career afloat to go and get their eyes checked thoroughly before splashing out on expensive courses. If your doctor hands you the ishara test under the normal light then ask to do it under the proper conditions otherwise it might catch up with you years down the line!

whipper_snapper
05-11-09, 14:54
A friend of mine, and one who I have sailed with many times, always fails the 'card' tests. He requested a lantern test and failed that too. And yet, he can distinguish red from green, apparently perfectly reliably. I regularly challenge him by day and by night to distinguish these colours and he appears to be every bit as good as I am (I have no problems with the standard test).

So what is going on ?

He is able to get commercial qualifications at any level in theory, but always endorsed to say 'not to stand watch alone at night'. Which seriously limits his employability.

Moodyjim
05-11-09, 14:56
Quite agree with Snowleapord, the white can be a bit "yellowy" at least when I did it 48 years ago!

nicholasdonohoe
28-02-10, 04:05
so is there any hope of being commercially endorsed if one is colourblind?

Samiam
26-08-10, 18:32
Has anybody used Chromagen lenses or the Azman color correction system based in the USA to take an MCA Eng 1 medical?? Are aid lenses or glasses accepted?
Look forward to hearing any responses.

johnchampion
27-08-10, 15:58
As another who did the lantern test a few times many years ago I agree with the previous comments on it and that it was needed for all deck officer tickets although once you had Masters FG there was no more testing, and indeed in those days there was no ongoing medical checks such as ENG1 today.
I passed my latest ENG1 a few months ago and once and can confirm it includes the Ishihara tests. You don't actually need ENG1 for an RYA commercial endorsement, you can get an ML5 which lasts longer but is not so comprehensive and can be done by an ordinary GP while the ENG1 has to be done by an MCA approved doctor which may explain why some GP tests are perhaps not so rigorous as previously suggested by some as regards testing conditions.
It was not unusual many years ago for someone to have been to sea school, completed an apprenticeship and then find out when up for 2nd mates that they were colour blind and therefor in need of a new profession as their chosen one had just closed it's doors on them. At that time glasses were not allowed for any of the eyesight tests either although they are now.
The investigations people have come up with so far seem to apply to the MCA STCW side and not to RYA tickets and there may not be an option with the RYA to try a lantern test if the Ishihara one has failed.
However while I feel sorry for someone who is colour blind in relation to this I fully support the position that any sort of ticket which qualifies someone to be on lookout or holding a watch should not be issued to any one if they are colour blind. If I were a ship owner I don't think I would be very happy entrusting several hundred millions to someone who could not distinguish which way another ship was going and as far as yachts and small boats are concerned the safety question has to be paramount when issuing someone a ticket and if you can't reliably make out what lights you are seeing then you cannot claim to be safe. There's just no way round it.

sarabande
27-08-10, 16:10
hmmm !

Since 1999 Dr. Thomas Azman has been using the ColorCorrection System™.
Dr. Azman has been 100% successful and guarantees success in passing the Ishihara Color Plate Test - the international gold standard.

Ariadne
28-08-10, 22:09
Sorry, I agree with the fact if you fail you fail - my life and my families lives are is in danger if you can't legally distinguish red/green.
The idea of the eye tests is so you actually see without any aids. It was explained to me many years ago - 'You are on board a ship, you loose/break scratch/etc, your glasses/vision aids/whatever - what are you going to do now; you can't see properly, and therefor you can't stand your watch so somebody else has to do it for you'.
As for the DDA, it doesn't even enter the argument in this case.

It's a big nasty old world out there, just learn to live with it.

timbartlett
29-08-10, 18:50
The idea of the eye tests is so you actually see without any aids. Do you think that should apply on the roads, as well? After all, cars don't have radar or AIS to help avoid obstructions and most pedestrians (not to mention most cyclists) don't even bother with lights!

noelex
29-08-10, 20:43
hmmm !

Since 1999 Dr. Thomas Azman has been using the ColorCorrection System™.
Dr. Azman has been 100% successful and guarantees success in passing the Ishihara Color Plate Test - the international gold standard.
The Ishihara is not a gold standard.iIt is a screenimg test. Yes it possile to cheat this test,but what does that achieve?

noelex
29-08-10, 20:57
A friend of mine, and one who I have sailed with many times, always fails the 'card' tests. He requested a lantern test and failed that too. And yet, he can distinguish red from green, apparently perfectly reliably. I regularly challenge him by day and by night to distinguish these colours and he appears to be every bit as good as I am (I have no problems with the standard test).

So what is going on ?

He is able to get commercial qualifications at any level in theory, but always endorsed to say 'not to stand watch alone at night'. Which seriously limits his employability.

People with a mild colour vision defect will distingish Red from green in resonably good illumination conditions or with resonably saturated colours.
The colour vision tests are designed to eliminate those people that will have difficulty under adverse conditions. Do you trust this person on watch at night when there is some haze/fog about?
Get them to wake you if they see a vessel at night would be my advice.

noelex
29-08-10, 21:18
Dort

I wrote to the MCA at the end of last week to ask for clarification on their policy. They have a document on their web site which says that the seafarer's vision test is Ishihara, but another document that describes the use of the lantern test to permit seafarers with a degree of red/green impairment to be assessed fit for lookout duties (which is the issue at point here). I'm interested in the answer from a professional perspective. I'll post the answer here when I get it.

Andy
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.

ean_p
30-08-10, 12:12
Mmmm i'm colour blind but can easily see the difference between red and green lights at sea....but to me the red and yellows are close and the white and the greens are close until quite close to.... so can easily see a port hand light on the side of a ship between the cabin and work lights but not so easily see a starboard light against the same background....likewise in a channel the green lights don't stand out clearly from the white.....and why or why don't we use blue ligts either....never any problem with blue lights!

Ariadne
02-09-10, 00:00
Do you think that should apply on the roads, as well? After all, cars don't have radar or AIS to help avoid obstructions and most pedestrians (not to mention most cyclists) don't even bother with lights!

Get a grip, who mentioned anything to do with driving a car???? If you want my opinion for what its worth, then yes I would agree with that if came about for driving a car - and for exactly the same reasons!
Most yachts don't have active AIS - and most accidents in a car don't involve flying a helicopter/diverting shipping/calling out a lifeboat or anything else that involves putting other peoples lives in danger to rescue you AT SEA!!!!

What is the problem here, if you don't meet the required standard then tuff. If I fail my next eye test then I'll have to accept it and get on with my life, same for an ENG1. Its a requirement for the job, and the job is at sea without a nanny state/do-gooder/bunny hugger/tree lover/litigation lawyer or anybody else to hold your hand/glasses for you when it all goes pear shaped and the brown smelly stuff hits the fan. The last thing you need to worry about is can the person in the wheel-house see you/anything or has he/she dropped their glasses and therefor is not able to take a watch and actually perform the job they are employed to do!

Get over it!

noelex
02-09-10, 06:57
Do you think that should apply on the roads, as well? After all, cars don't have radar or AIS to help avoid obstructions and most pedestrians (not to mention most cyclists) don't even bother with lights!

In many countries there are colour vision standards for drivers, especially commercial drivers (busses taxis etc)
The incidence of road accidents, particularly rear end collisions is significantly higher with some types of colour vision defect. It is argued however depriving someone of a private driving license is a significant reduction in there liberty, ability to work etc so in many countries without restrictions on private licenses, society tolerates a higher risk of accidents from these people.
People paying a fare for their journey have a right to expect the driver does not have a disability that significantly increases their chance of an accident. Commercial drivers also spend more time on the road, hence the restrictions.

st599
02-09-10, 14:09
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
08-09-10, 18:53
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
08-09-10, 22:03
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


[QUOTE=andygc;2634836]

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
09-09-10, 08:49
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
09-09-10, 09:18
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
09-09-10, 12:26
Again

It is not possible to cheat a properly conducted Ishihara

Oh God, I give up.

noelex
09-09-10, 13:12
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
09-09-10, 15:43
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.