Diseases of the eye : a hand-book of ophthalmic practice, for students and practitioners / by G.E. De Schweinitz.

  • De Schweinitz, G. E. (George Edmund), 1858-1938.
Date:
1893
Catalogue details

Licence: Public Domain Mark

Credit: Diseases of the eye : a hand-book of ophthalmic practice, for students and practitioners / by G.E. De Schweinitz. Source: Wellcome Collection.

Provider: This material has been provided by the Harvey Cushing/John Hay Whitney Medical Library at Yale University, through the Medical Heritage Library. The original may be consulted at the Harvey Cushing/John Hay Whitney Medical Library at Yale University.

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    which the operation has been done, single vision should result. It' it does not, the excessive effect must be overcome by a suture. Graduated tenotomies or partial tenotomies are performed by many surgeons, and adjustments (especially of the vertical mus- cles) are exactly made. The former method is advocated by Dr. Stevens. Many brilliant results have been secured I>y experienced operators, but there seems little doubt that a good deal of inju- dicious snipping of the tendons of the ocular muscles has been practised. Nystagmus.—This term is applied to a condition characterized by an involuntary, rapid movement of the eyeballs. The move- ment may be from side to side, or in a vertical or rotary direction. The condition may be congenital or acquired, and is bilateral in the vast majority of cases, although a few instances of uni- lateral nystagmus have been reported, with the movements usu- ally in the vertical direction. It is possible, however, inasmuch as slight forms of nystagmus are detected only by using the ophthalmoscope and watching the fundus, that some of these supposed unilateral eases have actually been bilateral. The movement is nearly always in the lateral direction. According to Gowers, the extent varies from 1 to 10 mm., and the frequency from 60 to 200 separate oscillations per minute. Congenital nystagmus is seen with cases of defective construc- tion of the eyeball—coloboma, microphthalmos, etc. It is also common in albinism. Nystagmus also occurs with opacities of the cornea and degenerations within the media, especially when such obstruction to the rays of light has been caused by diseases occurring early in life. Nystagmus may be acquired by the pursuance of certain occu- pations, especially mining, and is commonly known as miner's nystagmus. It generally occurs among those who use a dim light, and whose work necessitates keeping the eyes in an unu- sual position for many hours together (Snell). Finally, nystagmus is exceedingly common in diseases of the nervous system, particularly disseminated sclerosis and Fried- reich's ataxia. It occurs in many diseases of the brain, and has been noted with great frequency in tumors of the cerebellum. Nystagmus has been ascribed to chronic fatigue of the muscles 35