XIII. On a distinct form of Transient Hemiopsia

Abstract

It is certainly matter of surprise that a morbid affection of the eyesight, so striking as to engage the attention of Wollaston, Arago, Brewster, Herschel, and the present Astronomer Royal, should have received but little notice from that profession to whose province it exclusively belongs. But it must be borne in mind that the votaries of Natural Philosophy are especially qualified by their habits of accurate observation to con-­template attentively any strange apparition, without or within, and, I had almost said, are especially exposed to the risk of impairment (temporary or permanent) of the eyesight, by the severity of the eye-work and brain-work they undergo, and therefore possess especial advantages for the study of visual derangements; whereas the physician, unless personally subject to the malady, must depend, for his acquaintance with its phenomena, on the imperfect or exaggerated accounts of patients untrained to observe closely or record faithfully. The complaint cannot be a rare one; each writer on the subject, in addition to his own personal experience, has mentioned instances of the same affection among his friends. In the whole body of the medical profession there must be many who are at once liable to the disease and able to describe it. And it is not unimportant. I have seen a person, terribly subject to these attacks, shudder at the very name, and turn away in horror from a drawing of the ugly sight, quite content to bear serious illness “if only the 'half-blindness’ would keep away.” I think it will appear from the various accounts to which I shall refer, and from the different instances which I shall bring forward, that there are more forms than one, of transient hemiopsia.