The relation of errors of refraction and insufficiency of the ocular muscles to functional diseases of the nervous system / by D.B. St. John Roosa.

Roosa D. B. St. John (Daniel Bennett St. John), 1838-1908.

Date:: 1890

Credit: The relation of errors of refraction and insufficiency of the ocular muscles to functional diseases of the nervous system / by D.B. St. John Roosa. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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$York than in Paris, because New York men and women are not so well nourished by good and well-cooked food and sound red wine, as are the corresponding class in Paris. I am not prepared to dispute this opinion. It is important to bear in mind this distinction between accommodative asthenopia occurring in neurasthenics, women with uterine disease, malarial subjects, those re- covering from typhoid fever, and so forth, who, at the same time, like the rest of the world, have slight refractive errors and insufficiencies, and pure accommodative as- thenopia in healthy subjects, caused either by high degrees of hypermetropia, astigmatism of even moderate degree, great weakness of the internal recti, unequal refraction of the two eyes, or the like. Although Donders was the discoverer of the nature and the cause of asthenopia, he had no idea of its frequency. While he recognized the fact that headaches, melancholy sensations, and a long train of evil symptoms might result from asthenopia, he did not know how frequently these symptoms were caused by ocular fatigue. In his time the public were somewhat discouraged in getting medical aid for the relief of these symptoms, and readily gave up the use of their eyes for near work, and turned to agricul- ture or idleness, as a palliative for what could not be cured. Donders found in a shortened eyeball the chief cause for asthenopia; as he says, “ hypermetropia is usually at the bottom of asthenopia.” If he had known as much of the effects of astigmatism as he and Knapp had shown us of its nature, he would have said hypermetropia and astigmatism. At this very time, Graefe was in the midst of his in- vestigations of muscular asthenopia. Donders was care- ful to describe muscular asthenopia also. He believed that it depended chiefly on insufficiency of the internal recti muscles. Up to this day Dcnders’s classification has been pretty generally accepted, and all writers speak of ac- commodative and muscular asthenopia. But Donders underrated the importance of astigmatism in producing$