. Refraction and muscular imbalance, as simplified through the use of the ski-optometer. arlyobtained. For the convenience of the opera-tor, all minus or concave spherical powers areindicated in red; while plus, or convex pow-ers, are indicated in white. [8] Refraction and Muscular Imbalance The instrument is also provided with anopaque or blank disk which is brought intoposition before the sight opening by settingthe pointer of the supplementary disk atshut (Fig. 3c.) Summing up, all plus and minus sphericalpowers have been attained from zero to quarters, practically through the turn o
. Refraction and muscular imbalance, as simplified through the use of the ski-optometer. arlyobtained. For the convenience of the opera-tor, all minus or concave spherical powers areindicated in red; while plus, or convex pow-ers, are indicated in white. [8] Refraction and Muscular Imbalance The instrument is also provided with anopaque or blank disk which is brought intoposition before the sight opening by settingthe pointer of the supplementary disk atshut (Fig. 3c.) Summing up, all plus and minus sphericalpowers have been attained from zero to quarters, practically through the turn of thesmgle reel—a simplicity of operation largelyresponsible for Ski-optometer supremacy. [9] Chapter 11 CYLINDRICAL LENSES TT is commonly admitted that setting eachtrial case cylindrical lens at a common axisis the most tedious part of refraction. The automatic cylinder, one of the Ski-optometers latest and distinctly exclusive fea-tures, not only overcomes this annoyance butalso avoids the need of individually trans-ferring each cylindrical lens according to thevarying Fig. 7—Once you set the axis indicator as shown by ciottedfinders, each cylindrical lens in the instrument auto-matically positions itself exactly at that axis, as indi-cated by the arrow. By merely setting the Ski-optometers axisindicator (Fig. 7), each cylindrical lens inthe instrument automatically positions itself, [10] Refraction and Muscular Imbalance so that it will appear at the opening at theexact axis indicated. This is readily accomplished by placing thethumb on the small knob, or handle of theaxis indicator, drawing it outward so as torelease it from spring tension. The indicatormay then be set at any desired axis; and, onreleasing the handle, every cylinder in the in-strument becomes locked, making it impos-sible for any lens to appear at an axis otherthan the one specified by the indicator. This insures the absolute accuracy of theaxis of every cylinder as it appears before thepati
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