The detection of colour-blindness from a practical point of view / by F. W. Edridge-Green.

  • Edridge-Green, F. W. (Frederick William), 1863-1953.
Date:
1889
Catalogue details

Licence: Public Domain Mark

Credit: The detection of colour-blindness from a practical point of view / by F. W. Edridge-Green. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    thought that the fallacies of some of them would have been obvious to a child. Such a test, for instance, as that consisting of three or four colours painted on a board in a definite position. The inventor does not seem to have thought that a normal-sighted person may have told the candidate the position and names of the colours. _ I am sure that more attention would be paid to the subject if the ]public apx^reciated what colour-blindness is. No intelligent man could object to persons, who cannot see any difference between the colour of a scarlet coat and that of the grass, and cannot distinguish between the red and green Hghts at a distance of 100 yards, being excluded from services in which it is necessary to readily distinguish between those colours. Testing for colour-blindness is not an easy matter, even with the most efficient of tests, considerable experience being required to make a competent examiner. Without an efficient test, no amomit of experience will be of use. The subject is of such importance that I am_ sm-prised that more attention has not been paid to it from a practical point of view. With the methods which are in vogue at the present time there is no guarantee that the examiner himself is not colour-blind. I wonder how many of the 1,400 colUsions at sea, which occurred during the year ending June, 1888, were due to . colom'-blindness of the navigating officers. It is terrible to think that railway accidents and coUisions at sea should occur through laxity in testing those whose duty it is to distinguish between the coloured hghts. Shall we wait until some great railway accident draws universal atten- tion to the subject, and the worthlessness of the tests m use, before those tests are changed ? I would not travel by a train if I knew that the engine-driver was colom-- With regard to the persons who should conduct the ex- amination for colour-bhndness: there seems to me no doubt that the testing should be conducted by a medical man, specially trained in colour-bhndness. I must say agani, most emphatically, that it is useless for a person who is not acquainted with the phenomena of colom'-blmdness to test for the presence of this defect. In the following pages I have, for the benefit of those who have not been pe?sonally instructed by me, given the common errors which the examiner is Hable to fall into. But the cases