. Refraction and muscular imbalance, as simplified through the use of the ski-optometer. Fig. 8A—Inner cog-wheel construction, showing arrange-ment of Ski-optometer cylinders. This simple construc-tion assures accuracy and avoidance of the slightestshifting of axes. As each cylinder appears before the pa-tients eye, it simultaneously registers its focusat the indicator marked CC CYL shown inFig. 8. Examinations of greater accuracycould not possibly be made than those obtainedthrough the Ski-optometer, hence no refrac-tionist should hesitate to employ it throughoutan eniire examination—wherever
. Refraction and muscular imbalance, as simplified through the use of the ski-optometer. Fig. 8A—Inner cog-wheel construction, showing arrange-ment of Ski-optometer cylinders. This simple construc-tion assures accuracy and avoidance of the slightestshifting of axes. As each cylinder appears before the pa-tients eye, it simultaneously registers its focusat the indicator marked CC CYL shown inFig. 8. Examinations of greater accuracycould not possibly be made than those obtainedthrough the Ski-optometer, hence no refrac-tionist should hesitate to employ it throughoutan eniire examination—wherever trial-caselenses are used. The range of the Ski-optometers cylinder-lens battery includes up to 2D. in axis scale and a cell is located at the back [12] Refraction and Muscular Imbalance of the instrument for insertion of an additionaltrial-case cylinder lens, when stronger cylin-. Fig. 8—Turn this Single Reel as shown by dotted finger to obtain cylindrical lenses, which simultaneously register their focus as they appear. Each lens also automatically positions itself at axis designated. drical power is required. For example, if anadditional —2D. cylinder is added, it will in-crease the range up to 4D. cylinder; or iftwelfths are desired, an cylinder lensmay be inserted. In this connection, it is in-teresting to note that considerable experiment-ing with twelfths in the Ski-optometer provedthem to be needless, inasmuch as the instru-ments cylindrical lenses set directly next tothe patients eyes overcome all possible loss ofrefraction, as explained in a later paragraph. [13] Refraction and Muscular Imbalance Why Concave Cylinders Are Used Exclusively The Ski-optometer contains only concavecylinders, as it is universally admitted thatconvex cylinders are not essential for testingpurposes. In fact, concave cylinders should alone beused in making an examin
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