Subjective symptoms in eye diseases : being chapters on the disorders of vision symptomatic of diseases in the eye and central nervous system / by George A. Berry.

  • Berry, George A. (George Andreas), 1853-
Date:
1886
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Licence: Public Domain Mark

Credit: Subjective symptoms in eye diseases : being chapters on the disorders of vision symptomatic of diseases in the eye and central nervous system / by George A. Berry. 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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    less regained its functional activity. In this case the symptoms were evidently purely the result of pressure on the chiasnia. Nasal hemianopia is of such rare occurrence that it hardly deserves attention. It appears to be due to symmetrical lesions of the optic tracts, and has probably in most cases only been the beginning of complete optic atrophy. Optic Atrophy.—Except where there is marked diminution in the size of the retinal arteries, it is only when the pallor of the discs is extreme that we are justified in diagnosing the existence of optic atrophy from ophthalmoscopic examination alone, as the physiological limits of colour and excavation are extremely wide. Along with a low degree of central visual acuity, an excessive pallor of the nerve is certainly suspicious ; but there are many cir- cumstances under which those two conditions exist, either mutually dependent or not, unconnected altogether with atrophy,—for . instance, all those which give rise to a central negative scotoma. For a safe diagnostic as well as prognostic criterion we are thrown back upon the determination of the state of the field of vision. Our knowledge on this subject was first clearly formulated by V. Grsefe,1 and, indeed, so thoroughly was this subject investigated by him, that, with the exception of the slight refinement which has been introduced by the examination of the peripheral colour vision, little or no advance has since been made. One of the most important points which resulted from his observations was, that however much the central vision might be diminished, no fear of progressive atrophy, and therefore eventual total blindness, need be entertained if the boundaries of the field of vision remain normal. In progressive atrophy there is invariably a limitation of the field. The limi- tation often takes place all round (concentric limitation), but in other cases the field in one direction is more restricted than in the rest. The restriction which is taking place can frequently be most easily demonstrated for colours. This is, very probably, simply because, if the examination be made in ordinary daylight, the corresponding failure of the sense of form may, if slight, more readily escape detection. There does not appear to be any reason 1 Klinische Monatsbl. f. Augenh., 1865, and Archiv, vol. ii. P