Holmgren's wool test also known as Holmgren's colored wool test is a

color vision test A color vision test is used for measuring color vision against a standard. These tests are most often used to diagnose color vision deficiencies (''color blindness''), though several of the standards are designed to categorize normal color vision i ...

used to detect

color vision deficiency Color blindness or color vision deficiency (CVD) is the decreased ability to see color or differences in color. It can impair tasks such as selecting ripe fruit, choosing clothing, and reading traffic lights. Color blindness may make some aca ...

. Swedish physiologist

Frithiof Holmgren Alarik Frithiof Holmgren (October 22, 1831 – August 14, 1897) was a Swedish physician, physiologist and professor at Upsala University, most noted for his research of color blindness. He was a vocal opponent of vivisection, and particularly t ...

introduced the test in 1874. It was the first successful attempt to standardize the detection of color blindness. William Thomson simplified the original Holmgren test, and later named as Holmgren-Thomson test.

History

Holmgren's colored wool test is a color vision test method introduced in 1874 by the Swedish physiologist

Alarik Frithiof Holmgren Alarik Frithiof Holmgren (October 22, 1831 – August 14, 1897) was a Swedish physician, physiologist and professor at Upsala University, most noted for his research of color blindness. He was a vocal opponent of vivisection, and particularly the ...

(1831-1897). Holmgren studied the electrical response of the retina to light. Holmgren's test gained attention following

Lagerlunda rail accident The Lagerlunda rail accident occurred in the early hours of November 15, 1875 about 8 km west of Linköping in Östergötland, Sweden. Unclear signalling between a station master and a steam engine driver led to a train leaving the station a ...

in Sweden in 1875. Suspecting that the train's engineer (who had died in the accident) was color blind, Holmgren decided to examine the 266 employees of the Uppsala Gabole line, and as he suspected, thirteen of them were found to be color blind. Holmgren's test quickly established itself as a systematic and reliable method of detecting color blindness in railway and shipping workers. Following Holmgren's research, test was commissioned by the Swedish railway authority in 1875 and color blindness testing was made mandatory for railway and shipping workers in Sweden. The original Holmgren test was the first successful attempt to standardize the detection of color blindness. Holmgren developed his test based on the

Young–Helmholtz theory The Young–Helmholtz theory (based on the work of Thomas Young and Hermann von Helmholtz in the 19th century), also known as the trichromatic theory, is a theory of trichromatic color vision – the manner in which the visual system gives rise ...

of color perception. The Holmgen test was designed to matching rather than naming colors. The actual test was more difficult. Dr. William Thomson simplified the original Holmgren test. In 1879, the American government commissioned Thomson to conduct a color-blind inspection for railroads and shipping. Thompson worked to simplify Holmgren's method so that a "non-professional" test could be performed and the results can be forwarded to an expert for interpretation. Thompson reduced the number of matching colors and numbered each one. This test is one of the earliest examples of a psychological test used on a large group of people. This test was later named the Holmgren-Thomson test. British Board of Trade used Holmgren's wool test to test the color vision of seafarers from 1895 to 1913.

Test

In Holmgren's wool test, the patient is asked to match coloured skeins of yarn to the samples in the box. At first, the patient is asked to select from the 40 skeins, 10 skeins that best match the light green master A. From the remaining 30 skeins, the patient is then asked to select the 5 skeins that best match the red master C. Lastly, the patient is asked to select 5 skeins from the remaining 25, to match the rose master B. From the mistakes made, the doctor can diagnose the type of colour blindness. If the patient chooses blue or violet colors in the red matching test, it means that they have red blindness. If the patient choose gray or dark brown colors on the green color matching, it indicates that they may have a green blindness problem. If the subject prefers green or yellow colors in the violet color test, they are defective to violet.

References

{{reflist Color vision Diagnostic ophthalmology Optometry