The light reflex on the retinal vessels / by John B. Story.

  • Story, John B.
Date:
1892
Catalogue details

Licence: Public Domain Mark

Credit: The light reflex on the retinal vessels / by John B. Story. 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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    THE LIGHT EEFLEX ON THE RETINAL VESSELS. Ever since the invention of the ophthahnoscope, ophthahnologists have been familiar with the appearance of a light reflex or light streak on the retinal blood-vessels, but they are not, even at the present time, quite in accord as to the precise cause of this phenomenon. The history of the subject is briefly as follows:— The very earliest observer, E. von Jaeger, attributed the reflex to a reflection from the walls of the vessels, though he subse- quently, and I think erroneously, modified his theory by assuming that it came from the convex surface of the blood column, the vascular walls being, in his opinion, too transparent and too much of the same coefficient of refraction as the retinal tissue to produce the reflex. This theory of a reflection from the convex cylindrical surface of the blood, or of the vessel wall has been opposed by Loring* in 1871, who holds that the light streak is caused by refraction of light transmitted fi'om the illuminated background through the convex cylinder of the blood column, which in fact acts as a convex lens, and this view has again been advocated by Davis, in the Archives of Ophthalmology, of which paper an abstract can be seen in the Ophthalmic Review, 1891, p. 88. Loring supported his theory by the following arguments :— 1. The light streak is too broad to be a reflection from the convexity of the vessel or the blood column. 2. The blood column is too transparent and non-reflecting to give so brilliant a streak. 3. If the blood column l^eflected the streak, the latter would be best marked when the vessels are full; but in venous pulsation it disappears when the vein is most full. (Loring describes * Read before the Section of Anatomy and Physiology of the Eoyal Academy of Medicine in Ireland, Friday, March 25, 1892. Archiv. of Ophthalmology. Vol. 11., No. 1, p. <^!j.
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