[Historical Development of the Wool and Colour Plate Tests for Screening for Colour Vision Deficiencies in German Speaking Countries]. / Historische Entwicklung von Wollproben- und Farbtafeltests für das Screening von Farbsehstörungen im deutschsprachigen Raum.

Colour vision is a complex visual function that can be affected by congenital and/or acquired disorders. The frequency of congenital colour vision deficiencies has been investigated in rail and navy staff since the 1870s. Various test methods have been developed. Wool tests, flor contrast tests and colour plate tests have been used. A published colour plate test, based on Stilling's pseudo-isochromatic plates in combination with a flor contrast test, has been a common screening method for colour vision testing in German-speaking countries. This test is intended to detect congenital and acquired colour vision deficiencies in a simple and safe manner. More modern options, such as Internet and tablet PC have technical limitations, but will increasingly be used for screening for colour vision deficiencies.

[Web-based analysis of Stilling's color plates]. / Webbasierte Analyse von Stilling-Farbtafeln.

BACKGROUND: Color vision tests with pseudoisochromatic plates currently represent the most common procedure for the screening of congenital color vision deficiencies. By means of a web-based color vision test, new and old color plates can be tested for diagnostic quality without major effort. METHODS: A total of 16 digitized Stilling's color plates of the 11th edition from 1907 were included in a web-based color vision test (http://www.farbsehtest.de). The χ(2)-test was used to check whether the Stilling color plates showed similar results to the nine previously evaluated Ishihara color plates. RESULTS: A total of 518 subjects including101 (19.5 %) female subjects with a mean age of 34.6 ± 17 years, took the web-based test with the 25 plates. For all participants the range for the correctly recognized plates was between 5.2 % (n = 27) and 97.7 % (n = 506) for the Stilling color plates and between 64.9 % (n = 336) and 100 % (n = 518) for the Ishihara color plates. For participants with more than 5 errors (n = 247), the range for correctly recognized plates was between 2.0 % (n = 5) and 98.0 % (n = 242) for the Stilling plates and between 42.5 % (n = 105) and 100 % (n = 247) for the Ishihara plates. Taking all color plates and all participants into account there was a significantly higher incidence of erroneous recognition of the Stilling color plates (3038 false and 5250 true answers) compared to the Ishihara color plates (1511 false and 3151 true answers) (p < 0.001, χ(2)-test). CONCLUSION: The diagnostic quality of the tested Stilling color pates was very variable. Some of the plates could be used for the test edition of the Velhagen/Broschmann/Kuchenbecker color plates from 2014. Overall, the Stilling color plates were recognized with a higher incidence of error by all participants in the web-based test compared to the utilized Ishihara color plates, which in most cases was attributable to ambiguity of some symbols.

The Lagerlunda collision and the introduction of color vision testing.

In histories of vision testing, the origins of occupational screening for color blindness are often traced to a fatal railroad accident that occurred in Sweden on the night of 14-15 November 1875. The scene of the accident was the estate of Baron Lagerfelt in Östergötland, but the critical events were played out at Linköping (the normal passing place for the northbound and southbound expresses) and at Bankeberg (a small station to which the passing place was reassigned at a few minutes' notice). First to arrive at Bankeberg, the northbound express slowed almost to a halt, but then inexplicably accelerated forwards towards the Lagerlunda estate, despite a sequence of signals from the stationmaster, Uno Björkelund, and a lineman, Oskar Johansson. Soon after the accident, the ophthalmologist Frithiof Holmgren suggested that the engineer of the northbound express, Andersson, or his oiler, Larsson, had been color blind. Neither survived to be tested. Using the records of the subsequent trial and other archival materials, we have re-examined the role of color blindness in the Lagerlunda incident and conclude that the accident cannot be attributed to color blindness alone. Yet the accident undoubtedly had a central role in the introduction of color vision testing by European and North American railroads. To persuade the railroad management to introduce universal screening of employees for color blindness, Holmgren used a dramatic coup de theatre and some unashamed subterfuge.

Unilateral colour vision defects and the dimensions of dichromat experience.

The standard view, that protanopes and deuteranopes see only varieties of yellow and blue, is often taken to be supported by the reports of people with one colour-blind eye and one normal (or near-normal) eye. Judd's survey of 89 years of unilateral cases might seem authoritative: 'The color perceptions of both protanopic and deuteranopic observers are confined to two hues, yellow and blue', corresponding to 575 and 470 nm (DB Judd, J Research National Bureau Standards, 41: 247-271, 1948). A critical re-examination reveals, however, that the cases do not support Judd's claim: the original publications indicate in most cases substantial (though limited) red-green discrimination with the dichromatic eye under favourable conditions (e.g. with large fields), and evidence of red/green sensation; in the main case where researchers find sensation only of yellow and blue, it is by using experimental methods that are almost guaranteed not to reveal the full range of the subject's sensation. More recent reports (from the 1950s and later) show that, if the colour experience space of a dichromat eye collapses to a 2D slice through the 3D space of a normal trichromat, the slice may be not flat but curved (and curved in more than one dimension): there are further reasons to think that dichromat colour experience, whether unilateral or bilateral, may not collapse to a plane at all. The unilateral cases are unclear in many ways, but they certainly give no support to a 'yellow-and-blue' view of dichromat experience.

Color vision and Frithiof Holmgren's discordant retinal microstimulation findings.

Frithiof Holmgren was a nineteenth-century Swedish professor of physiology who, after a sabbatical year at Helmholtz's laboratory in Heidelberg, devoted himself to studies of color vision and color blindness. Following Blix's successful demonstration of cutaneous receptor specificity by means of point stimulation, he decided to apply an analogous technique for psychophysical examination of the human retina. His findings appeared to support the Young-Helmholtz hypothesis of three primary colors and invalidated Hering's alternative four color opponent hypothesis. However, contemporaries (Hering, Isaachsen) could not reproduce Holmgren's results, and his findings fell into disrepute. They have now been confirmed, but their previous theoretical significance was not supported.

La falsa discromatopsia del pintor Eugène Carrière / No disponible

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John dalton: though in error, he still influenced our understanding of congenital color deficiency.

John Dalton was born in the 18th century and was recognized mainly for his work on the chemical atomic theory and "Dalton's Law" for the partial pressure of gases. However, during his lifetime he was already recognized for his theories on "colorblindness," with which he was afflicted. He was perhaps the first to report personal observations from experimentation on his color vision deficiency. His theory regarding its pathogenesis was posthumously proven to be incorrect after observations performed on his enucleated eyes. Further generations later, DNA analyses by PCR conclusively recorded the specific color deficiency (deuteranopia) with which Dalton was affected.

[Did Leon Wyczókowski suffer from solar maculopathy?]. / Makulopatia sloneczna u Leona Wyczólkowskiego?

Noted Polish painter, Leon Wyczólkowski, during his long-standing in Ukraine used to paint pictures gazing directly at the sun in order to intensify visual sensations. Damage to the eyes caused by sunlight induced him to become a patient of a famous ophthalmologist in Kiev. Past disease led to blue color vision impairment just like it happens to people who previously suffered from solar maculopathy. We suppose, it could gradually force the artist to resign from color painting and to take up drawing.

One of Australia's greatest cricketers was a protanope: a genetic detective story solved with the help of Schmidt's sign.

Abnormal colour vision is under-represented among first class cricketers and interviews with cricketers, all of whom had a mild colour vision defect, suggest there may be times when they lose sight of the red cricket ball against green surrounds. It is possible that severe abnormal colour vision precludes playing cricket at its highest competitive level. It is known that Bill Ponsford, who played Test cricket from 1924 to 1934 and was one of Australia's greatest batsmen, had abnormal colour vision. We have diagnosed him to be a protanope by tracing the abnormal colour vision exhibited by some of his descendents. We used Schmidt's sign using the Medmont C100 colour vision test to identify carriers of the protan gene to trace the protanopic gene to Ponsford with greater certainty. That such an accomplished batsman and highly regarded out-fielder should have a severe colour vision deficiency suggests that abnormal colour vision might not be, or at least need not be, a handicap to playing cricket at the most competitive levels.

The dilemma of color deficiency and art.

No "major" painter is known to be color deficient. Are there truly no color deficient artists, or have they not been recognized? The historical literature cites criteria for recognizing color deficiency in artists, but they are hard to apply without knowing the intentions of an artist. The work and commentary of a color-deficient artist who works currently in Paris are presented as an example. He uses a limited palette of colors, based on advice from colleagues as much as his own perceptions, and he uses colors in ways that do not always fit with expectations for color deficiency. Biographies of earlier painters suggest that there were a few whose color sense was poor, but these painters used assistants to help. The color sense of others, such as the English landscape painter John Constable (1776-1837), has been questioned because of a preponderance of suspicious color, such as murky green. However, there are good reasons to doubt that Constable was color deficient. It is instructive to know how proven color deficiency has influenced an artist's style. When medical information is unavailable, the best advice for the diagnostically-inclined observer is just to enjoy the art.