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January 22, 1898


Author Affiliations


JAMA. 1898;XXX(4):197-198. doi:10.1001/jama.1898.72440560025001i

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In 1892 I conceived the idea of simplifying the determination of the static relation of the optic axes by placing a Maddox rod behind two rotating prisms, thus avoiding the necessity of employing a series of prisms, and presented this conception in a paper read before the Ophthalmological Section of the American Medical Association, at Detroit. In 1893 this idea was embodied in my phorometer published in the Archives of Ophthalmology. This conception has been adopted by Wilson in the construction of his instrument. The dial is so graduated as to indicate the combined effect of the two prisms in every possible relation to one another, and each quadrant of the dial is lettered to indicate the character of heterophoria. In testing for hyperphoria, the index will point to R.H., L.H., or 0, denoting the degree of right or left hyperphoria, or the existence of neither. Similarly in observations relative

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