Regulations as to defects of vision which disqualify candidates for admission into the civil or military government services / by J. Fayrer.

  • Fayrer, Joseph, Sir, 1824-1907.
Date:
1887
Catalogue details

Licence: Public Domain Mark

Credit: Regulations as to defects of vision which disqualify candidates for admission into the civil or military government services / by J. Fayrer. Source: Wellcome Collection.

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    vision is impaired either by a convex or by a concave lens if stronger than can be overcome by an effort of accommoda- tion. By the direct method with the ophthalmoscope, the person’s eye nnder examination being directed to a dis- tant point, and the observer’s eye being emmetropic and his accommodation relaxed, if the mirror of the ophthalmoscope be brought close to the eye under examination, a clear and enlarged image of a portion of the fundus is seen, which moves in the same direction as the observer’s head. At a distance of a few inches, supposing the observer be emmetropic, he will not be able to see the details of the fundus of the eye with definition. By retinoscopy the shadow is absent or very faint, and if it move, it is in a direction opposite to that of the mirror. If in any doubt the eye should be examined when fully under the effects of atropine. Myopia. Parallel rays are focussed in front of the retina; divergent rays alone being focussed on the retina. The myope requires a concave glass to enable him to overcome his error of re- fraction ; the weakest glass with which he sees best is the measure of his myopia and expresses its degree. Bor instance, when we speak of a person being myopic to the extent of 2 D., we mean that with a concave glass of two dioptries he can see Snellen’s test-types at their correct dis- tance. By the direct method of ophthalmoscopic examina- tion the mirror being brought close to the myopic eye, the details of its fundus cannot be clearly defined until a concave lens be placed in front of the observer’s eye : the weakest glass with which the details of the fundus can thus be dis- tinctly defined is the measure of the myopia. In high