Eyestrain (commonly called asthenopia) / by Ernest Clarke.

Ernest Clarke

Date:: 1892

Credit: Eyestrain (commonly called asthenopia) / by Ernest Clarke. Source: Wellcome Collection.

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$examine into the state of vision and of refraction, and into the strength of the recti muscles and into the conditions under which they are called upon to act. Day says : When attacks of vomiting and headache come on in young persons who strain their eyes, the symptoms, in some of these cases, are thought to be due to brain disease, whereas they are really owing to defects of vision, or errors of refraction, which result in myopia, hypermetropia or astigmatism. ^ Hence it is most important to thoroughly test the eyes of all who complain of headaches or any other asthenopic symptom, and if this were done at first instead of last, as is so often the case, a large amount of disappointment to the medical man and the patient would be avoided in many cases. It is important to remember that the headache of brain tumours is independent of any visual effort, and that optic neuritis is to be looked out for as a very probable association. Frontal or temporal pain, which may be more of the character of a neuralgia, is often caused by a decayed tooth. It is possible that eyestrain may also exist, and we then have the two reflex causes acting together, the one increasing the effect of the other. Hence in all cases where correction of the ocular defect does not yield a satisfactory result, we should have the teeth overhauled by an experienced dentist. The diagnosis of the particular variety of asthenopia is only made by a thorough examination of the refraction and muscular equilibrium of the eyes. V. Graefe has suggested the following points as a help in diagnosing convergence from ciliary strain :— * (i) The symptoms of muscular asthenopia last longer ' Headaches, 1888, by W. H. Day, M.D., p. 215.$

Eyestrain (commonly called asthenopia) / by Ernest Clarke.

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