The diseases of the eye / by Edward Nettleship.

  • Nettleship, Edward, 1845-1913.
Date:
1890
Catalogue details

Licence: Public Domain Mark

Credit: The diseases of the eye / by Edward Nettleship. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

    468/508 (page 444)
    Bull (of Cliristiaiiia) lias introduced a quantitative test, l)ased upon the smallest amount of colour wliioli, mixed with fjfrey, can be recof,''niB('d by the normal eye (to bo obtained from Triibuer and Co.). Rows of coloured spots, those in each row <;ontaining a dillerent ({uantity of grey, are painted in oil eoloui's on a black background. The normal eye will distinguish the .colours even in the greyest row ; the colour-blind will, accord- ing to the degree of defect, confuse complementary colours in some, or all of the rows. I find Bull's tables very useful, but like all painted and lithographed surfaces they reflect too much light, and thus, unless held exactly in the right ])osition, they •flliine and their colour is altered. Unless very carefully used Bull's and JeafEreson's tests are, I think, less trustworthy than A good set of wools. The regulations as to vision applicable to candidates for Admission to the various public services at home and in India lire fully set forth in a pamphlet on this subject lately compiled by Sir Joseph Fayrer with the assistance of Mr (ouper and Mr C. Macnainara, and published by Churchill, 11, New Burlington Street. An explanation of the coloured plate is given on p. 442; it is not intended to be used as a test, but ■only as an illustration of the colours commonly ■confused.