INTRODUCTION.* PAINS spreading to parts contiguous to the eyes, as the result of strain to those organs, in much the same manner as pain from a wound extends to the environing tissues, have long been observed. In many of the older treatises on the diseases of the eye, headaches, nausea, and vertigo are mentioned as parts of that group of symptoms which we now designate as asthenopia. It is to be remembered that the phenomena of accommodative asthenopia, while recognized, were, until its nature and causes were more fully explained by Donders in his remarkable work published in 1864, described under different names, such as hebetudo visus, amblyopie presbytique, etc., and were by many supposed to possess a distinct pathology, such as hyperæmia of the retina, or an increase of some of the humors within the eye. There was a general agreement, however, in the grouping of the phenomena and in regarding excessive or disadvantageous use of the eyes themselves as the exciting cause. The grouping consisted, as it now consists, of pain, tension in the *Submitted to the Royal Academy of Medicine, July, 1886. forehead, dazzling and confusion of vision, inability to continue the use of the eyes, to which by many authors were added the more general sensations of dizziness, nausea, headaches in other parts of the head than the forehead, and general malaise. Antoine Maître-Jan* (1707) gives a good description of the complaint, which he thinks arises from increased intra-ocular tension resulting from strain of the eyes. A century later, Weller † (1832) enumerates tension over the eyes, headaches, nausea, and vertigo, to which train of phenomena Sichel ‡ (1837) adds insomnia, as the group of symptoms arising from excessive use of the eyes. A An old author, # in speaking of the people who require glasses for reading, but neglect to use them, remarks facetiously, "Their eyes ache, their head aches, and every bit of 'em aches." Piorry ▲ (1850) quotes from his writings twenty years earlier, his views regarding certain nervous disturbances, "oscillations nerveuses" having their seat in the eye, the ear or in some branches of the fifth nerve. A form of migraine which he calls "irisalgie" has, according to him, its origin in irritation arising either from the iris or from the retina. The migraine results in such cases from excessive or improper use of the eyes. He cites the case of a medical professor who 215. Traité des Maladies de l'eil," 1707, p. 260. "Maladies des Yeux, traduite par Riester," Paris, 1832, tome ii, p. "Traité de l'Ophthalmie," etc., Paris, 1837. # Dr. William Kitchner, "Economy of the Eyes," 1824. habitually suffered from migraine after reading his lectures written in very fine characters, and who was free from the affection when he did not read the lectures. He also mentions the case of another physician who suffered severely from the same affection uniformly after several attempts to use glasses not adapted to his eyes. Piorry made no practical application of these views. These few examples will serve to illustrate the extent to which the eyes were supposed to affect contiguous or more remote parts, up to the era when, by the discovery of the ophthalmoscope by Helmholtz, by the recognition of the rôle played by the ocular muscles in inducing fatigue about the eyes, a subject especially elucidated by Von Graefe, and by the discovery of hypermetropia by Donders, the knowledge of the causes and treatment of asthenopia was infinitely promoted. Notwithstanding these great advances, the phenomena of asthenopia continued to be stated in much. the same order as before. Graefe and Donders enumerate the symptoms substantially as they are given above, and Stellwag* concludes his excellent description of accommodative asthenopia as follows: "If the work is continued" (after the sense of exhaustion has commenced), "these feelings" (confusion of vision and swimming of objects before the eyes, with a feeling of pressure, fullness, and tension in the forehead) "soon increase to actual pain in and over *Stellwag, first American edition, 1868, p. 622. the eyes and are soon accompanied by a very painful feeling of dazzling; finally headache, dizziness, universal malaise, and even nausea occur." Beyond question, however, the most important recognition of the fact that distant pain might be induced by straining the eyes was by Anstie,* who asserted that "functional abuse of the eyes" is a powerful source of irritation tending to induce neuralgia. He also says that hyperopic sewing-girls are specially liable to that affection, and relates that he himself was relieved from neuralgia by desisting from the use of his eyes in reading. Notwithstanding these assertions, Anstie seems to have made no practical application of the important facts thus enunciated, and even seems to regard the conditions as accidental and factitious. Possibly a greater familiarity with the defects which are known to be influential in the production of asthenopia would have encouraged this learned author to make some practical application of a principle which he seems to have very imperfectly recognized. Thus far, then, there had been recognized certain isolated facts concerning irritations arising from disadvantageous use of the eyes, in relation to parts somewhat removed from them. No general principle of sympathetic or reflex irritation had, however, been formulated, and the first printed announcements of the existence of such a principle was made by myself, in a paper presented to the Albany Institute in the early part of 1876, and "Neuralgia," D. Appleton & Co., New York, 1872. |