Not everybody sees all the colours of the visible spectrum in quite the same way, yet throughout history an ability to identify specific colours has had many important uses.
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Here, for example, is a colour chart designed by Professor Stilling of Strassburg (the modern French city of Strasbourg, then part of the German Reich) published in his Grundzüge der Augenheilkunde, 1897, a copy of which may be studied in the BOA Library.
To learn more about the false avenue of Dalton's research see our separate web page.
Once the nature of the problem was more properly understood, vision scientists came to identify two main types of colour 'blindness'.
Protanopia = so-called 'red blindness'. Patients see only two hues (blue and yellow) and are almost blind to red radiation. About 1% of the adult male population is affected.
Deuteranopia = so-called 'green blindness', a misnomer since deuteranopes see green light as brightly as anyone with normal vision. Rather, they confuse reds with greens. All long wavelengths look yellowish and and short wavelengths bluish. Slightly more than 1% of men are affected but the condition is unusual in women.
The BOA Museum contains a very varied range of tests for these two conditions, some very simple, others much more sophisticated.
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Edridge-Green Colour Vision Bead Test
by Down Bros Ltd
Late 19th - Early 20th c.
This comprised a varnished wooden case with a hinged lid and two body sections. The upper section had four compartments and a trap-door base. This was covered by a cardboard top with four holes for red, yellow, green and blue, through which beads of the appropriate colour could be dropped. The lower section was a pull-out drawer by which the beads could be retrieved. A pair of tweezers was provided for the precise selection of the beads.
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Holmgren wool colour vision test
Late 19th c.
This test consisted most simply of skeins of coloured wool, including samples for light confusion, dark confusion and matching. Some versions of the test had numbered skeins for ease of reference to the accompanying instructions, but the first two digits of the numbers were random, to confuse the patient. Variations on the test were soon offered for sale by companies such as E.B. Meyrowitz Ltd.
Alaric Frithiof Holmgren (1831-1897) was a Swede who founded a physiological laboratory at the University of Uppsala in the 1860s. He was noted for his early work on colour vision and its importance to transportation. In 1877 he published Om färgblindheten i dess förhallande till jernvägstrafiken och sjöväsendet (soon afterwards issued in English as Colour blindness in its relation to Accidents by Rail and Sea). His testing methods were similarly described in English by Charles Roberts in 1881.
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Donders Wool Test
by D.B. Kagenaar
c.1880s
Another variation was invented in 1879 by the Dutch ophthalmologist F.C. Donders (1818-1889) at the University of Utrecht. This example bears the maker's name of D.B. Kagenaar and comprises 24 woollen skeins, wrapped around wooden splints.
The photograph shows the memorial statue to F.C. Donders in Utrecht.
Other colour tests utilised pins, marbles or specially marked dice supplied with a soft dark mat on which to lay them out. Some were almost like children's toys. Although testing children for deficiencies in colour vision is important, historically it was not uncommon for people to have reached adulthood without the condition being diagnosed.
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Fletcher-Hamblin Simplified Colour Vision Test
by Hamblin Ltd
c.1983
A more sophisticated test (despite its name) was the Fletcher-Hamblin Simplified Colour Vision Test designed by Professor R.J. Fletcher of City University. This comprised three square plastic 'units' divided into coloured squares, the differences between which were really quite subtle. The test was supplied with a pad of record forms for accurate recording. The robust units were not easily soiled and were considered suitable for use with children or mentally handicapped adults. Unusually, the test was designed specifically for use under tungsten lighting.