Abstract
The theory of "invisible" eyeglasses, which in 1827 was expounded by Herschel, the English physicist, was again advocated at the end of the eighties of the last century by three German scientists almost simultaneously. All three independently reached the conclusion that contact glasses are of value by working on different problems, the idea of the invisibility of the eyeglasses not being considered. A. E. Fick, ophthalmologist of Zurich, was studying the problem of correction of so-called irregular astigmatism. One of the principal conditions of clear vision is that the shining, crystal-clear frontal lens of the eyeball, the spherically vaulted cornea, must be perfectly healthy. If the cornea is flattened in one direction, which may be congenital or the result of an operation, the so-called regular astigmatism, originating from the aforementioned causes, can be corrected by cylindric eyeglasses. But the cornea, because of its superficial position, is frequently exposed to

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