Impact of congenital colour vision deficiency on education and unintentional injuries: findings from the 1958 British birth cohort
BMJ 2004; 329 doi: https://doi.org/10.1136/bmj.38176.685208.F7 (Published 04 November 2004) Cite this as: BMJ 2004;329:1074All rapid responses
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Dear Sir
As described in our paper [1] the children in the 1958 British birth
cohort were tested at 11 years for colour vision defects (CVD). We have no
information about whether or not they were informed of their CVD status
and appropriately counselled, as assumed by Tey. We re-iterate that the
limited literature [2] on the subject suggests that recall and/or
understanding of information provided after screening at 11 years may not
be sufficient to usefully inform career decisions made at 16 or later.
We agree with Cole that individual specialist assessment of colour
vision undertaken when occupational choices are being made is the proper
basis for career counselling – this is not achieved by school screening as
it currently stands. Indeed it is possible that some individuals with
colour vision defects might be inappropriately deterred from a career
which they could have pursued on the basis of the findings of the school
screening test alone.
1. Cumberland P, Rahi JS, Peckham CS. Impact of congenital colour
vision deficiency on education and unintentional injuries: findings from
the 1958 British birth cohort. BMJ 2004: 329:1074-5
2. Holroyd E, Hall DMB. A re-appraisal of screening for colour
vision impairments. Child Care Health Dev 1997; 23:391-8
Competing interests:
None declared
Competing interests: No competing interests
The Editor,
British Medical Journal
Dear Sir,
Cumberland et al. (BMJ 2004;329:1074-1075) comment on the lack of
evidence that congenital colour vision defects (CVDs) restrict children's
educational performance. Each year we are told of those first-year medical
students with CVD on the grounds that their learning histology might be
hampered. No such student has ever reported difficulty with projected 35mm
slides or at the microscope with a slide set. However, red-deficient
students sometimes are the first to remind one to replace the batteries in
the laser pointer. It would be interesting to hear from histopathologists,
retired or active, who have a CVD.
In two respects the 'increasing use of colour in education' may not
disadvantage learners with CVD. Having made thousands of diagrammatic
histology PowerPoints in distinctive colours http://wberesford.hsc.wvu.edu
, I find students with normal vision graciously handicap themselves by
learning only from 6/page black-&-white printouts. Secondly, the
figures in current anatomy and histology textbooks now frequently lapse
into anaemic pastel.
Yours truly,
William A Beresford MA, DPhil
Professor of Anatomy
West Virginia University
Competing interests:
None declared
Competing interests: No competing interests
While Cumberland et al concluded there was no significant
disadvantage in acadamic achievement for children with colour vision
deficiency they made no mention of another important school activity,
namely sport.
A relative of mine despite being generally athletic at school
performed miserably at cricket and suffered some degree of opprobrium as a
result. It was not until many years later while watching a floodlit
cricket match in Australia which was played using a yellow ball that he
suddenly understood the game, as for the first time he could see the ball.
Batting or fielding when one has to react to a red ball on a
predominantly green background can be virtually impossible with deficient
colour vision.
Knowledge at the time of his deficient colour vision would have been
helpful to all concerned.
Competing interests:
None declared
Competing interests: No competing interests
Sirs,
I would like to comment on the findings by Cumberland et al which
concluded that statiscally colour vision deficiency defect (CVD) did not
confer any disadvantage in relation to educational attainment and
unintentional injuries 1. We cannot deny the fact that, statiscally there
was very little to differentiate between those with CVD and those without.
However I would like to point out that the sample population used were
individuals who were already diagnosed with CVD and that they had been
appropriately counselled and thus helped in developing effective adaptive
strategies and behaviours while at school. Therefore, the data on
unintentional injuries using this sample population may not represent the
true extent of possible unintentional injuries if these individuals were
not found or diagnosed to have CVD at school.
So I would like to suggest that for true data to be collected, a new
sample population of previously undiagnosed CVD and unintensional injuries
should be researched upon. However if screening were to stop, what impact
would this have on the broader population?
Yours sincerely,
Adrian Tey
1. Cumberland P, Rahi JS, Peckham CS. Impact of congenital colour
vision deficiency on education and unintentional injuries: findings from
the 1958 British birth cohort. BMJ 2004; 329: 1074-5
Competing interests:
None declared
Competing interests: No competing interests
Cumberland et al conclude that congenital colour vision defects (CVD)
confer no functional disadvantage and challenge the rationale for, and
value of, population screening for these disorders. The study however
contains an important flaw. Whilst the Ishihara test is a useful
screening test, it is substantially less satisfactory in defining severity
of CVD. The authors draw conclusions regarding the “minority with
severely impaired colour vision”, but fail to define whether or how this
was measured. Our study of the performance of colour-blind doctors in
assessing coloured pictures of clinical signs (1,2,3)identified that
doctors with more severe colour blindness lacked confidence in relation to
the assessment of clinical photographs, and, at least in some situations,
may be more prone to errors of clinical judgement. Unlike Cumberland and
colleagues, we would recommend that medical students should be aware of
their status in relation to CVD, and that for those with CVD, further
testing should be undertaken to alert them to the severity and form of
their condition. Practitioners with CVD, especially when it is more
severe, should take special care to ensure safe clinical practice.
Yours sincerely,
John Campbell, JAB Spalding and Fraz Mir
1. Campbell, JL, Spalding JA, Mir, FA, Birch J. Doctors and the
assessment of blood glucose testing sticks: does colour blindness matter?
Brit J Gen Pract 2000; 50: 393-5.
2. Campbell, JL, Spalding, JA, Mir, FA, Birch J. Doctors and the
assessment of clinical photographs – does colour blindness matter? Brit J
Gen Pract 1999; 49: 459-61.
3. Campbell, JL, Spalding, JA, Mir, FA. The description of physical
signs of illness in photographs by physicians with abnormal colour vision.
Clin Exp Optom 2004; 87: 335-8.
Competing interests:
None declared
Competing interests: No competing interests
We recognise that individuals with colour vision defects (CVD) can
experience difficulties in everyday life. These vary according to the
nature and severity of the condition as well as the personal circumstances
of the affected individual, as illustrated by the personal accounts of
some of the respondents to our paper.(Sellars,Wiegersma, Yoshimitsu,
Boulton). These also highlighted the adaptive strategies which allowed
these individuals to pursue their chosen careers.
In order to justify whole population screening for CVD several
criteria have to be met (www.nsc.nhs.uk): in particular, an important
impact on major life course outcomes at the population level (ie on
‘average’) which can be avoided by early detection. Thus we investigated
highest educational attainment and risk of serious accidents requiring
hospital care in a large and representative population. It is also
necessary to demonstrate that screening is the most effective way to
identify and inform those with CVD. Data in this area are scarce, but in
the only study of its kind in the UK of which we aware, despite screening
at school entry and at 11 years, not all children with CVD were identified
and not all of those informed of their CVD at age 11 years recalled or
were able to use this information when making career choices at 16.1
Alternative approaches include informing individuals about CVD as part of
the school curriculum in health education and career guidance. Most
affected children will have a positive family history, so parents may be
aware of potential difficulties and be able to access specialist advice
via their family doctors, or in the UK, free of charge through
optometrists.
Most respondents raised the issue of preclusion and difficulties
associated with some occupational choices. This is currently the rationale
for screening for CVD in the UK. Unfortunately, an editorial decision by
the BMJ meant that our data on employment history and occupational choice
presented in our original manuscript were not included in our paper. A
separate report of these findings is currently under review. The
prevailing international differences in statutory occupational preclusions
highlighted by respondents (Siedenburg), for example in relation to
medicine, commercial driving and aviation, serve to identify
inconsistencies in the evidence base. Nevertheless, in some countries
balancing the rights of an individual to pursue their chosen career with
the social and economic costs of ‘mistakes’ attributable to CVD is
currently actively debated.2 We agree that it is important for some young
people to know their precise colour vision status before making
occupational choices. This requires specialist assessment for a particular
context and is not the aim of school screening as currently practised in
the UK. Alternative approaches are needed to inform young people about
potential occupational difficulties and pathways to specialist evaluation.
1. Holroyd E,.Hall DMB. A re-appraisal of screening for colour
vision impairments. Child Care Health Dev 1997;23:391-8.
2. Cole B L,. The handicap of abnormal colour vision. Clin Exp Optom
2004; 87:258-275
Competing interests:
None declared
Competing interests: No competing interests
Actually a lot of discussion is going on whether strict colour vision
requirements are mandated in aviation. For the time being the JAA
provisions require the same standards for colour vision for commercial and
private pilots. Other systems had the same safety outcome with less strict
requirements for private pilots. However, the discussions regarding the
article lack the differentiation of several grades of colour deficiencies.
The majority of colour deficient individuals (around 7 % in a population)
have a minor deuteranomalia with only little functional deficiencies.
There is hardly any benefit from preventing those with minor merely
deficiencies from becoming e.g. surgeons or private pilots. Colour
blindness (Protanopsia, Deuteranopsia etc.) might have greater impact on
the functional abilities of affected individuals.
Competing interests:
None declared
Competing interests: No competing interests
Dear Editors,
I read this article with interest, as an optometrist with a colour
vision defect (Protanopia). I have developed strategies in my clinical
practice to correctly identify certain features (e.g., retinal
haemorrhages), which are potentially equivocal in appearance. As for my
dress sense, whilst my wardrobe has more than its fair share of blue (a
colour which I have no problems identifying), I am not renown for my bad
taste in clothing!
The authors raise the issue of the value of screening for congenital
colour vision defect (CVD). An Ishihara test is simple and effective in
identifying CVD, and is used routinely in clinical practice. Many
children attend eyecare practitioners, or may have their vision screened
in early childhood. These are ideal opportunities to identify CVD, and
allow them to make an informed choice about their future careers.
My personal experience is that within the general population (and
even among health professionals), there is great misunderstanding of what
a CVD is, and the degree of handicap it may have. To be simply labelled
as being "colour blind" is a stigma which no person deserves!
Fortunately, I was aware of my CVD before I commenced my Optometry degree,
and I was able to receive appropriate counselling.
Competing interests:
None declared
Competing interests: No competing interests
Cumberland, Rahi and Peckham 1 were unable to find a
significant association between colour vision deficiency (CVD) and
either educational attainment or the occurrence of personal injury.
They conclude that normal colour vision is not a pre-requisite for
safe driving or safe working. They say their findings challenge the
rationale of population screening for colour vision deficiency. The
conclusions are quite a leap and not at all helpful for people with
CVD. If you ask them about their problems almost all report some
problems with colour: 30% report problems recognising road traffic
signal lights and 13% have difficulty seeing brake lights of cars;
over a third say their colour deficiency affected their choice of
career and one in four report that they have problems with colour
in their present job.2 Three quarters have everyday problems
making judgements about colour. There are some occupations
from which those with colour deficiency are precluded because
colour recognition is absolutely critical to the job and a vast array
of occupations for which colour vision deficiency is a significant
handicap,3 including the practice of medicine 4 and careers in the
graphic and creative arts. The educational attainment of those with
CVD may not be effected in the long term but they suffer
embarrassment and anxiety when their teacher identifies objects
by colour or they are asked to use specific colours.3 There is
evidence that colour vision deficiency is a risk factor for driving.3
The studies that failed to show it is a risk factor had samples too
small to identify the expected level of risk.5 School children should
know if they have colour vision deficiency so they can be helped
more quickly to find adaptive strategies and be able to take it into
account when planning their career.
1. Cumberland P, Rahi JS, Peckham CS. Impact of congenital
colour vision deficiency on education and unintentional injuries:
findings from the 1958 British birth cohort. BMJ 2004; 329: 1074-5.
2. Steward SM, Cole BL. What do colour vision defectives say
about everyday tasks? Optom Vis Sci 1989; 66: 288-95.
3. Cole BL. The handicap of abnormal colour vision. Clin Exp
Optom 2004; 87: 258-275.
4. Spalding JAB. Confessions of a colour blind physician. Clin Exp
Optom 2004; 87: 344-349.
5. Cole BL, Maddocks, JD. Defective colour vision is a risk factor in
driving. In: Cavonius CR, editor. Colour Vision Deficiencies XIII.
Dordrecht: Kluwer Academic; 1997. p 471-81.
Competing interests:
None declared
Competing interests: No competing interests
To use the word screen or not to use
As a 1958 birth date (but not part of cohort I don't think), optometrist who trained under Barry Cole in Melbourne I feel duty bound to respond.
I think the issue here relates more to the terminology used. Rahi et al clearly use the NSC definitions of screening (which has been used to the detriment of future amblyopia detection in the UK). The paper makes the assumption that what "testing" for CVD is done at age 11 (by non-clincians, by no means universal and with no capacity to grade severity) is "screening" and therefore extrapolates to a conclusion that such screening may not be necessary on strict screening definition grounds. It is clear from all the respondents that they know that the testing was neccessary for them and that all children should know whether they are CVD or not. They don't need to know because it will stop them getting injured in later life they need to know because of the life choices that will be thrown at them, and fairly quickly. This is no good reason to extrapolate to the conclusion drawn.
NJR
Competing interests:
None declared
Competing interests: No competing interests