The fundus oculi, with an ophthalmoscopic atlas illustrating its physiological and pathological conditions.

  • Frost, W. Adams.
Date:
1896
Catalogue details

Licence: Public Domain Mark

Credit: The fundus oculi, with an ophthalmoscopic atlas illustrating its physiological and pathological conditions. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

    62/446 (page 38)
    adjacent fundus. Other things being equal, a disc will appear lighter when the fundus is very dark. If, for the present, we exclude from consideration discs which may be considered exceptional, we shall still see that there is great variation. The most usual colour is a rosy tint only slightly paler than the rest of the fundus, for example, Plate I., Figs. 1 and 2. The colour may be slightly deeper than this and duller (Plate II., Fig. 4); or it may be a deep rich red, as is well seen in Plate II., Fig. 6. A disc that looks light by contrast is shown in Plate III., Fig. 5, and Plate IV., Fig. 8. In exceptional cases the colour is a dull dirty red, as in Plate VII., Figs. 18 and 19. The same colour is seen in part of the disc in Plate VIII., Fig. 22, the central part of Plate V., Fig. 14, Plate VIII., Fig. 24. It will be noted, however, that discs of this colour generally present other unusual features, so that they can hardly be considered as typical. The form and the extent of this intermediate portion of the disc necessarily depend on the size, shape, and position of the physiological cup. If there is no cup, the intermediate zone may extend up to the centre of the disc (Plate II., Fig. 4, Plate III., Fig. 7, Plate V., Fig, 12), or there may be a zone of con- nective tissue forming a white, or pale, band round the central vessels. More commonly this part of the disc forms a broad belt surrounding a central cup, which may be large or small (Plate I., Figs. 1 and 2). It is not unusual for the cup to open outwards, under these circumstances the intermediate zone is displaced to the nasal side- (Plate XL, Fig. 30). Differences in the level of the disc surface are important in connection with inflammatory swelling of the head of tlie nerve, but in the normal condition they hardly come under consideration, for, unless special care be taken in the examination, the inter-