HC Deb 14 December 1911 vol 32 cc2694-5W
Mr. LYNCH

asked the President of the Board of Trade whether, in reference to the various offices under his control, he can state what proportion of candidates tested for vision are colour blind; whether any classification of results is obtainable as, for instance, with regard to degree or kind of colour blindness, or the association of this defect with any other physical condition; and, if so, whether he can give the statistics for the last five years, supplemented by any comments of the medical authorities which may be useful in the scientific regard of the question?

Mr. BUXTON

The only examinations in colour vision conducted by the Board of Trade are those for persons serving or intending to serve in the Mercantile Marine or in the fishing industry. Particulars of

these examinations are published in an Annual Report on the Sight Tests, a copy of the latest issue of which I am sending to my hon. Friend. As candidates for certificates of competency are required to undergo the sight tests on every occasion on which they present themselves for examination, many persons appear more than once in the total number of examinations, and the figures are therefore no guide to the general incidence of colour blindness. I am not aware of any data showing the association of colour blindness with any other physical condition, but information is available, as to the nature of the colour defects of candidates who fail to pass the tests. These are classified on the Young Helmholtz theory of colour vision according to whether complete or incomplete red or green blindness is present. The whole question of the sight tests at present in force is now being considered by a Departmental Committee. A table giving the statistics desired by my hon. Friend is appended:—

—— 1906. 1907. 1908. 1909. 1910.
Number of Examinations in Colour Vision 6,410 6,564 6,288 6,028 7,393
Number of failures. 57 76 44 71 112
Nature of defects—
Complete Red blindness 10 29 15 20 32
Incomplete Red blindness 9 5 4 15 17
Complete Green blindness 25 31 18 23 42
Incomplete Green blindness 13 11 7 13 21