ChiefDM

Tomorrow I'm off to City for a full colour vision assessment. I will post detials of test etc once I'm done for those who wish to know.

Fingers crossed......

ndr1804

oh,,,,,, best of luck chief DM. report back every detail please.

regards nsr1804

Scottish.CPL

cheifDM

same for me, all the best, i would say that if you pass the CAD test, then great, but i would like to know, what the setup is, specifically if the remote that you use to select the answers is connected to the laptop/pc, thats important..

ChiefDM

Morning all!

Well, here is my account of the colour vision assesment that I took at City. I chose City simply because at £125 +VAT for various tests it seemed like I would get a better understanding of my CVD that I would if I paid Gatwick £130 just for a pass fail on the CAD.

Got to City and was taken into a small lab type room where I did the following tests. For all of these the room was darkened and the tests were illuminated by what appeared to be a daylight type bulb (unsure of the exact name).

Started of with the Ishihara plates, most of which I couldn't make out. What I would say at this point is that while many people say lots about how you can't practice these on a computer as the lighting and colours will be all different etc etc, I would say this is probably only relevant to people with very very slight CVD (which it turns out mine isn't but we'll come to that in a bit!)

Next up was a test similar to the IP's but with symbols, triangle circle square etc pretty straight forward. Can't really guage how I did in this yet as my full results are being sent out to me in the post.

Next up was a test involving looking at a book with 5 small (about 6 or 7mm across) coloured dots on each page (black backgroud) with one dot in the middle and the other four layed out to the top bottom left and right. I had to choose the dot closest in colour to the centre. The important word here is colour, not shade or brightness. For example the centre spot might have been green, with a brown a red a green and a purple for effect as the coloured dots around it. Obviously the green one would be the right option, but those with green CVD will know that identifying the green one isn't easy, so you tend to go for the one that looks closest in shade instead, which invariably turns out to be the brown or the red! lol

Next up was the D-15, standard 'here's 15 coloured discs, arange them in order so that the next one is closest in colour to the previous.

Then came the moment we've all been waiting to hear about. The legendary CAD test. Now before I go into it let me just explain that I in actual fact did the CAD test twice yesterday. Not because I was close to a pass but because the standard City CAD test differs slightly from the CAA CAD Test. I'll go into these in a sec.

So the City CAD test comprised of sitting on a stool with my chin resting on a support looking at a screen that was about a meter and a half away that had the familiar CAD square in the middle of it, however it was quite small, very small in fact, I would say that the whold grid was no more than 2 inches at most, which viewed from a meter and a half starts to shrink rapidly! The remote I had only had four buttons on it and was connected via a cable direct to the back of an old DOS based PC. And away we went. As has been already posted here somewhere back among the million other pages, you see (or don't in my case) a coloured square moving its way across the diagonals of the grey, almost white noise like, backgroud. The box moves to one of the corners and then you have to identify which corner the box moved to by pressing the corresponding button on the remote. The test only shows you one box at a time and doesn't move onto the next one until you have pressed a button on the keypad. So you can take a break at any time simply by remembering which button you have to press next but not pressing it until you are ready to start again. A lot has been said on here regarding being able to guess the right answer if you don't know, while I agree that its true, your chances of getting it right are one in 4, I must have pressed that button at least 15 times in a minute and been sat there for at least 8 minutes, thats 120 times, at least. A good portion of those were guesses, I would estimate over 50% so at least 60 were a guess...... now I'm no mathmatician but the chances of getting 60 complete guesses right are, I suspect, quite large.

The lady conducting the test explained that it was normal that there would be some I couldn't see as they neeed to find the threshold at which my CVD hits. It's difficult to offer any advice for how to approach the CAD as everyone will be different, but I found it easier to starte at the little white dot in the middle and let the 'grey noise' almost become a blur, as opposed to trying to locate the coloured square as it flies accross the box(it moves quite quickly!).

Once I was done with this, the lady said that as I'd expressed an interest in aviation that I could also sit the CAD they use at Gatwick if I wished. An interesting comparison I though so why not! Off to another room where there was a similar setup with a few small differences. Firstly the computer connected was a shiny laptop running Windows not DOS. Secondly the remote used to control the test was indeed a wireless device (essentially a bluetooth numeric keypad with some red plastic buttons glues to the 1,3,7 and 9 keys). Thirdly, the monitor on which the test was done was a nice Flat screen monitor, adn fourthly the test grid itself was substantilly bigger on the screen, I would say a good 4 or 5 inches across. I did 2 seperate runs on this version, one to look at my blue yellow vision and the other for the red green. The test worked in the same way, in that if you press a button on the control it moves on to the next one (meaning that if there were a problem with the control, or that the button presses weren't being recognised by the laptop the test itself would just sit there and not move on).

Results for this one were given to me straight after. Turns out my Blue Yellow vision is in fact better than normal with a value of 0.8 (1 being normal, lower being better and higher being worse), however my red green (green inparticular) vision was a country mile away from being good. I scored a whoping 22 and a bit on that one, meaning my green colour vision is 22 times worse than most people. 'Surely you should have known it was that bad before you went you fool!' I hear you cry. Problem is (and other CVD people may or may not agree with this) that knwoign you have CVD and knowing how bad it is are 2 completely different things. because someone with CVD will never see what you are supposed to see there is nothing to compare it against and so while you may know there is an issue there is littel way of knowing how bad it is, until that is, you take a test like the CAD which can put a value on it.

Anyways, I feel better now at least knowing that i'm not borderline and that I can look into other things. I now have a couple of options:-

1:- Lobbying to have all the aviation red green colours changed to a blue yellow system so I can see them and pass tests without issue (anyone up for writting a few thousand letters with me? LOL)

2:- Exploring the possibility of becoming an Aircraft Engineer of some sort (I have an IT background, not sure if its any help though), anyone have any advice on this one?

Any questions feel free to ask!

ChiefDM

Scottish.CPL

ok so you did the cad test twice then, to different setup, one on a pc with a wired up remote and the other like at gatwick, wireless remote,

you said the results where r/g 22, and y/b 1 unit, so what did you get on the other test,

did you get another set of results from the other cad test ?

ChiefDM

Thats correct. The results i got were from the Gatwick version of the test, which I have to be honest here was the easier one of the two given the larger grid size. I didn't get the numerical result from the City version as it was run on a PC that looked like it had just be delivered by the Ark and didn't give them, I assume I will get those in my report.

I did however get to see the output graph from the City version which matched quite closely to the Gatwick versions graph.

Scottish.CPL

hi mate, sorry for the late reply our bb was down.

So they had two versions, there one and the gatwick one, i would be interested in the city ones as well.

yeah the gatwick version is as you say a bigger display, pesonally it made me feel a tad sick,...

so you did ishihara, city university test, richmond PIP test, D15, and the CAD, no lanterns then..

my results from my cad, red/green 7.44, so 1.44 over pass and .44 over retest. lol

im still not happy that the controller for the gatwick version is bluetooth, becuase how do i know that some of the responces were picked up by the sensor, i would have wanted the remote connected so at least i new it was a fair run.... and it was done through a normal tv, so how do i know that the colour temperature and gama setting were done correctly, im my opinion caa had opened a can of worms.

AnthonyGA

I suspect that the reason for using relatively small displays is that color vision is confined mostly to the central portion of the visual field. The fovea contains cone cells (which see color) almost exclusively, whereas the peripheral areas of the retina contain mostly rod cells. So a large display with colors moving out of the central portion of the visual field might cause everyone to fail, even people without CVD, because color vision declines substantially in the outer portions of the field. This is also why astronomers use averted vision to see faint stars (looking slightly away from the star allows more rods to see it), and why moving objects in your peripheral vision are easier to spot at night than objects that are right in front of you.

The nature of digital transmission systems is such that they are generally all or nothing: either the signal gets through without error, or it doesn't get through at all. An incorrect choice transmitted with an intact protocol is statistically unlikely, as it would require multiple, unusual circumstances. Either the connection should work perfectly, or it should not work at all. With some lossy protocols this changes, but I doubt that this particular protocol is lossy.

Scottish.CPL

so what are you trying to say, yes you agree with the first statement and its a flaw, or what, second any level of technology is not fail safe,

2close

It seems that a very fundamental and significant flaw with the CAD Test and the blatant hypocrisy of the CAA Medical Department is being missed.

They have, on public record, stated that the only safety critical operation involving colour discrimination is correct identification of PAPI lighting. However, they are adamant that the PAPI safety issue is so critical that no risk of error is permissible.

Yet they are quite happy to introduce a test which not only contains an element of guesswork but one where the operator actively encourages the candidate to guess.

Look at the realistic possibilities of practical testing of an individual's ability to identify PAPI lighting. Could it be tested during a flight test? Of course it could. Would that be difficult to administer? Of course not. Given the extremely small number of persons who would need such a test it would be simple to implement and I am certain those persons would be more than happy to cover the costs of the flight and the examiner.

But you could go on here for ever and a day.

Rest assured, NOTHING is going to change without direct action.

Scottish.CPL

i agree, really i do, the amercans do that, gun signals from the tower. The staff at the amc are great, and i know for a fact they are annoyed that some cases they get were they know the person cv is safe but JAR states other wise. and i agree with ur comments with the CAD,

Scottish.CPL

guys and girls, right need some help, ive just been reading the jaa medical manual on the pdf file, and was reading the othlamology report, first i ve never got the chance to read it ok, so i was ready that for the ishihara test, it states the the number of plates passed, and the number of errors must be recorded, and the results used in accordance with the test guidlines, well 13/15 plates contitutes a pass, i'm right on this ??

second the homes wright lantern, it states should be set to high, and then the presentations shound be shown, im i correct, when i did the lantern i was tested @ low brightness???

people feedback on this cause i am cross referencing from the JAA bible... from the manual

Testing with pseudo-isochromatic plates should be performed according to the instructions given
by each test. It is important that the quality of the illumination is correct: either northern daylight or
an artificial daylight source should be used. Ordinary incandescent lamps or fluorescent tubes
make these tests easier to pass, especially to deuteranomals. The daylight source should give an
illumination equivalent to the standard illuminants ‘C’ or ‘D’ of CIE (Commission Internationale de
l’Eclairage). The plates should be shown at right angles to the visual axis of the applicant, at the
correct distance and for the time specified in the test. The applicant should not wear tinted
glasses. The number of failed plates serves to classify the subject as normal, defective or
‘doubtful’ according to the specifications of the test.

the lantern notice thr retest part

The lantern-tests may be retaken after 6 months


If any error is made naming green as red, or red as green, the applicant will be
assessed as ‘colour vision unsafe’ without further testing.
If any other error is made, two further runs (i.e. 2 x 9 pairs of lights) on ‘HIGH’
brightness will be carried out. If no error in either run is made, the applicant will be
assessed as ‘colour vision safe’.
If one or more errors are made, the applicant will be assessed as ‘colour vision
unsafe’ unless dark room facilities are available.
If dark room facilities are available, the applicant will be dark adapted for 15 minutes and
one final run of the nine pairs of lights in dark room conditions at ‘HIGH’ brightness is
carried out.

i am so pi55ed of now, becuase i know for a fact i was tested on low, and never on high settings, i believe i have now been cheated on my medical...... read this space

osmosis

I am interested to know how many of you reading this are from Australia and have gone through the DCA/DoA/CAA/etc mill or given up trying to?

2close

If a medical professional has failed to carry out and administer a test in accordance with published manufacturer's instructions that professional may have acted negligently and may be taken to task for medical negligence and a claim for damages made against him or her.

Ask this question - what would you do if a surgeon changed a procedure during an operation to one he thought would suit his objectives better, which resulted in a serious detrimental effect to yourself? Would you simply accept it and walk away? Of course not! You'd be down your solicitor's offices the following morning.

Scottish.CPL

ive pm u, but no im not going to accept it, the other thing is that my level of trust with amc is now in question, i can get access to another h-w lantern, but not a byne, and i am certinaly not wanting to touch the cad again..

ChiefDM

My City CAD results arrived over the weekend, they were better but not by much 18.8. Obviously there is a lot being said about the CAD. From my point of view I saw no problem with it. If I was going to pass I would have passed if I was marginal, I'd have had to retest 3 more times, to reduce the chances of that marginal pass being down to guesswork. If I fail then I fail, end of story. The equipment that was used as has already been said is either it works or it doesn't. You press a button, if the test moves on the remote works if not, it doesn't. You have no more safeguard that the button you pressed is the one that registers using a wired remote than you do using a bluetooth one.

I agree it does seem odd that if the PAPI is the only thing they say you need to be able to distinguish, why this is not tested specifically rather than making people jump through the hoops of the CAD test. That said I was glad I did the CAD test as there is no other test out there at the moment that can quantify how bad CVD is. Even with the error allowance it gives you a much better idea as to the extent of your CVD. It may still be ballpark but its better than giving you a country the ballpark might be in

From my point of view the bottom line is that I'm nowhere near passing it so unless regs change in the VERY near future it's not going to happen for me. Shame but I have to move on and consider other things. Sadly I simply don't see them changing anything with regards to CVD for a LONG time!

AnthonyGA

Replace "medical professional" with "pilot" and see if you really still want that to happen. Be careful what you wish for. The same actions that may bring you emotional comfort in one situation can bring you emotional grief when the tables are turned.

Color vision tests constantly improve. As they increase in accuracy, persons who have been on the borderline of the aviation standard for color vision may go from meeting the standard to not meeting it, or vice versa. For those who might have been able to pass a less accurate test but cannot pass improved tests, this is unfortunate, but it's not a problem with the tests.

Tiny variations in lighting and mysterious bluetooth failures do not seem to prevent persons with normal color vision from passing, nor do they prevent persons with acceptably mild cases of CVD from passing. At the same time, no change in lighting will help people with severe CVD—they will fail the tests no matter what.

As the accuracy of tests increases, the results for people who are on the borderline become more consistent. For the lucky ones, they pass more consistently, since they truly meet the imposed vision standards. For the unlucky ones, they fail more consistently, since they truly do not meet the standards. For every person who is excluded because of increased accuracy in the tests, there will be another who can now pass because of that increased accuracy. For every person who can no longer fly because he cannot pass the tests, there will be another person who now has the opportunity to make a living from flying, because now he can pass the tests. The evolution is always in the direction of greater objectivity and fairness.

Complaining about imaginary defects in the tests will not help people in the unlucky category. Their only hope is to get the standards changed so that they will be able to meet them. It is only the standard that matters, not the test. For someone who truly cannot meet the standard, the situation will only get worse in the future, as fewer and fewer tests are inaccurate enough to let someone below the standard pass.

Scottish.CPL

well sorry, but i will question anything that will cause a discrepancy, especially on the cad that involves the tech/optician advising to guess on the direction of a signal, erm no...

second, i am asking for a retest on the lanterns, specifically the beyne, as quoted on the page in the JAA medical book. I have have the Ishihara test for to other careers, the police and the transport service and i have read every single plate, the last time i went to gatwick was for an faa medical renewal, and did the plates and i struggled with one of 2, after i left, i dawned on me that the reason was, no light was used, you know the special light that simulates daylight, surley the doctor should have picked this up, afterall im just a patient.

also my trust level for a certain person, dealing with they eyesight, no names, because of the attitute the person gave me...

ndr1804

Hi everyone......still feel like I'm being tricked into failure..........Tell you what,,,,,I'll stick to flying around at PPL level only, to be able to fly at night or IR and sod the commercial...........With a medical without restriction on it for the last 27 years...........I can define a runway day or night very well thankyou with or without PAPI lights........some sort of Irony there don't you think...? It still baffles me as to why so much is put onto CV in flying anyway. Some of the poor landings I've experienced probably with a none CVD pilot have happened well after they have passed the PAPI lights. Anyway the majority pilots probably with CVD find other ways of conducting a safe landing. If the weather is so bad and you are IR don't we have something called ILS to which it is often displayed on a black and white analog instrument " Or so you have the latest glass cockpit do you well then its displayed as two different bars in the horizontal and vertical and it wouldn't matter a damn what colour they were. Surely in this day and age we can safely fly around the skies without so much colour required,? yes it looks nice, but does it really stop the deciphering of information to the extent of being unsafe.......?

regards NDR1804

dobbin1

I recieved my JAR CPL last week, together with a whole page of restrictions - no public transport, no night, UK only, G reg only, must have a radio at ATC aerodromes. This is good enough for me to become a paid flying instructor, at least until EASA comes along - who knows what they will do.

I fly a lot an an airfield with PAPIs and I don't have any difficulty telling the white from the red. I suspect I would have trouble telling green from white at night though and I suppose this could be a problem during a night flight. For info, I failed 13 of the 15 plates and the lantern tests at Gatwick. I have not bothered with the CAD test, since I have no ATPL ambitions.