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.

    466/508 (page 442)
    44-2 closi! to llio l)aok of the mirror ns possihle; the lenses eveuly iiiouiited, foiitred truly, either tlioronf,'hly covered up or easily iieeessihie for cleaning, and not less than 5 unn. in diameter. 4i;. I'l-ntlMETEliS. The most convenient forms have an arranp;cment for regis- tering the Held autoniiiticiilly on a chart fixed behind tlu! centre of the arc. A very coni])lete, hnt conijilicated and exi)ensive one, is Mcllardy's (about £8); Triestley Smith's, much simpler and clieai)er, is for most juirposes as useful. (Both these are made by Pickard and Curry.) Blix's self-registering peri- meter is well spoken of hy Dr JJerry,* and may be had front Mr I'l-escott, ;5;3, liothian Jioad, Edinburgh. 47. The ('lock-I'ACE for testing astigmatism (]). 317) can be had from Carpenter and Westley, 2i, Regent Street, Waterloo I'lace, and from I'ickard and Curry. 48. The set of Coloured Wools recommended by Prof. Holmgren, of IJpsala, for testing colour-blindness, can he ob- tained for about live and sixpence from 1*. Dorllel, Unter den Ijindcn Ki, Bc'rlin, or from Curry and Paxton. In the coloured ])late, copied by permission from Prof. Holmgren's work ' JJe la ceeite des coulenrs, &c.,' 1877, the horizontal stripes I, Ila, and Ili, show the colours which it is, as a rule, most convenient to use as tests; and the short vertical stri])es are the colours most likely to be confused with these by those affected with the ordinary forms of colour-blind- ness, 'i'hus. No. 1 will be confused with one or more of such bull's, pinks, &(•., as Nos. 1 to 5; in slight degrees of colour- defect the confusions will be limited to these ])ale colours. In higher degrees of colour-blindness stronger or more saturated colours will be confused; Il«, for example, or even a stronger rose colour may be confused, on the one hand, with a ftdl blue or purple, Nos. 6 and 7 ; or, on the other, with full grey or green, Nos. 8 and 9. Taking a dillerent series of e(|ually saturated colours, the scarlet lib may be confidently identified with dark green or brown, Nos. 10 and 11, or with light bright green and yellow brown, Nos. 12 and 13. The confusion colours, Nos. 1 to 13 on the plate, are given merely as samples of the colours most commonly confused with the res])ective test colours; in ])ractice a much larger series- sliouid l)e eni]iloye<l; the more critical the ])atient, the larger is the number of shades and colours requisite; even markedly colour-blind jiersons do not always match exactly the same colours with the tests. Coloured worsteds are used because it * ' Subjective Symptoms in Eye Disease,' p. 91 (188G).