Color blindness : remarks / by B. Joy Jeffries at the twenty-ninth annual meeting of the board of the supervising inspectors of steam vessels.

Jeffries, B. Joy, 1853-

Date:: [1881]

Credit: Color blindness : remarks / by B. Joy Jeffries at the twenty-ninth annual meeting of the board of the supervising inspectors of steam vessels. 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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$Color-blindness is very hereditary 5 of importance, where a son fol- I lows the parents' or grandparents' profession. It follows, as cases in I families show, the general law of heredity, hence the high ratio in a I community containing many color-blind families. A practical point here I is, that after accident from collision or otherwise, and those implicated are killed or drowned, we may, perhaps, judge whether it was due to 1 €olor-blindness by finding whether they belonged to color-blind fami- ihes, and had blood relatives who are defective. Color-blindness may exist congenitally in one eye. Persons who can be put into the so-called hypnotic condition may be temporarily ren- dered color-blind thereby. Moreover, the color-blind who can be thrown into this condition may be made to see colors whilst hypnotized. Color-blindness, besides being congenital and hereditary, may be acquired. It is a symptom of some diseases of the brain and the optic \ nerve. Men, after any exhausting disease like typhoid fever, should be tested before again assuming their duties. The necessity of i)eriodic examinations, for instance with pilots as often as they are relicensed, is thus readily understood. This, quite aside from the necessity of testing their visual power, which may have decreased from many causes during the preceding year. Professor JS'uel, of Louvain, Belgium, sent me the following account of a case under his care, which was reported to the Eoyal Medical ; Academy: 'Moseph Dhur, of Turinne le Grosse, set 20, laborer on the Grand Central Road, consulted me January 12, 1878. I found that he had I been in the Hospital St. Pierre, at Louvain, a year before, with trouble in the back of the right eye, {une nevrite retrohulhaire.) From this he re- covered to having vision two-thirds of the normal. After a month at the hospital, he returned to his work and continued at it a year without his -condition being noticed. During this year, however, Dhur had to act one day as a guard. In the evening he put out a green instead of a red lantern, and returned into the guard-house. Having for some reason to go out a few minutes later, he passed near the lantern, when ; suddenly he was in doubt as to the color of the signal. Looking at it more closely with his left eye, (which was then healthy,) and comparing the two difterent faces of the signal, he found that he had in reality shown the green instead of the red light. These facts he even now recalls very well, and distinctly remembers how he could not distin- guish between the red, green, and white lights with the right eye, and €ould only tell them by looking close-to with his left. The circum- stance so affected him that he consulted a physician, who dismissed him with the remark that he had probably been drinking. On examination, I found the visual acuteness of the left eye normal, of the right six-ninths of normal. Visual field of left eye for white, norma] 5 of right eye only 30 degrees up, down, and inwards; outwards, 40 degrees. The color sense is greatly altered in the right eye. Eed and green are confounded with gray; ^dolet appear blue; the patient could only distinctly distinguish yellow and blue. In the left eye the color sense for red and green was diminished; the object had to be larger than what the normal eye could recognize. ''Here, then, we have an employe with defective color sense, from a disease of the nervous centres, continuing his occupation for a year; but the first time he had to give the signal, displaying green for red. The danger can be readily appreciated. Had he been an engineer an acci-$