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Although telescopic or magnifying spectacles have been manufactured by Carl Zeiss for the past twenty years, and have been prescribed by ophthalmologists whenever required, an optometrist in New York who recently made a slight modification of dubious value created a furor, especially among the newspapers. The presumably conservative New York Times led in the wild acclaim, publishing a large photograph of the "inventor."
The Zeiss telescopic spectacle is essentially nothing more than an improved opera glass in which, by using very high powers the two component lenses have been brought much closer together, thereby making the instrument shorter and less heavy, and thus wearable in a spectacle frame. Opera glasses are constructed according to the principle of the galilean telescope. In Galileo's telescope (fig. 1), the light rays from the object that is being viewed first traverse a convex lens and are converged to form
Eggers H. AN INEXPENSIVE TELESCOPIC SPECTACLE. Arch Ophthalmol. 1933;10(4):515–517. doi:10.1001/archopht.1933.00830050091011
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