Ophthalmic lenses, dioptric formulae for combined cylindrical lenses : the prism-dioptry, and other optical papers (1900)
Prentice, Charles Frederick, b. 1854 · Philadelphia : Keystone · leaf 130
icient to cause consecutive linesof small type to appear intermingled with each other. Shortly after this paper was first published, the author devised the fol-lowing simple apparatus (phorometric chart) for estimating the deviationsof the visual axes. The chart here described has, however, been… … Fig. 14. Fig. 14 sliows a blackboard 20 inches square having on its surface eightvertically and eight horizontally arranged dots, which are separated by 6centimeter distances, so that each interval of space between the dots repre-sents 1^ at 6 meters distance from the eye. A light is placed behind…
Lenses
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