A tangent plane for accurately mapping scotomata and the fields of fixation and single vision and for indicating the precise position of double images in paralysis / Alexander Duane.

  • Duane, A. (Alexander), 1858-1926.
Date:
[1906]
Catalogue details

Licence: In copyright

Credit: A tangent plane for accurately mapping scotomata and the fields of fixation and single vision and for indicating the precise position of double images in paralysis / Alexander Duane. 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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    with a red glass before one ej-e. With his head fixed he follows the light until it appears double. The point where this occurs on each meridian in succession is indicated by a pin inserted into the cur- tain. By carrying the light on into the field of double vision the kind and amount of diplopia can be graphically shown. This is done by marking the situation of the light itself with a black pin and the situation of the double image (in this case the false image) with a white one. In this way we not only record the exact distance and Fig. 2.—Chart used for plotting scotomater. Actual size of chart 5%x3% Inches. The meridians are drawn for every fifteen degrees, and the limits ol the scotoma are Indicated on each meridian by dots representing the pins thrust through the corresponding meridian on the tangent-plane curtain. relative disposition of the double images, but also show which is the fixing eye. For if with the red glass before the right eye, the patient says that the point where we have actually placed the electric light looks red, it is evident that the right eye is fixing, while if ii looks white the left eye is fixing. In plotting the position of the double images, the checker board of 2 inch squares on the back of the curtain is a considerable help.