A HYDRAULIC-OPTICAL EXPERIMENT WITH A FLEXIBLE LENS
Nobody doubts that the lens of the human eye changes its shape in the process of accommodation. Nevertheless the lens lacks any known physiologic properties through the mediation of which it could, in response to stimulation, change its shape spontaneously. A flexible lens, such as that of the human eye, as a mere object of study for the mechanical engineer can change its shape, without ceasing to be a lens, under the influence of any one of three classes of external mechanical factors: (1) by radial pull applied to its circumference, (2) by a contracting push applied to its circumference and acting toward its axis, (3) or by hydraulic pressure applied to one of its two surfaces, provided that the yielding of its peripheral parts is more obstructed than the yielding of its more central parts. (Hydraulics, of course, includes hydrostatics.)
MEYER MF. MECHANISM OF ACCOMMODATION STUDIED EXPERIMENTALLY. Arch Ophthalmol. 1932;8(1):53–65. doi:10.1001/archopht.1932.00820140061007
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