. Refraction and muscular imbalance, as simplified through the use of the ski-optometer. the one specified by the indicator. This insures the absolute accuracy of theaxis of every cylinder as it appears before thepatients eye. Subsequent shifting of the axiseven to a single degree is impossible, al-though it is a common occurrence where trial-case lenses are employed. Obtaining Correct Focus After setting the axis indicator, the only re-maining move is to obtain the correct cylin-drical strength or focus. This is readily ac-complished by merely turning the Ski-optom-eters larger or extreme out
. Refraction and muscular imbalance, as simplified through the use of the ski-optometer. the one specified by the indicator. This insures the absolute accuracy of theaxis of every cylinder as it appears before thepatients eye. Subsequent shifting of the axiseven to a single degree is impossible, al-though it is a common occurrence where trial-case lenses are employed. Obtaining Correct Focus After setting the axis indicator, the only re-maining move is to obtain the correct cylin-drical strength or focus. This is readily ac-complished by merely turning the Ski-optom-eters larger or extreme outer single reel,which contains concave cylindrical lensesfrom .2SD to 2D in quarters (Fig. 8a). Itshould again be borne in mind that a down-ward turn increases concave cylinder power,while an upward turn decreases it. The oper- [11] Refraction and Muscular Imbalance ation of the cylinder reel is greatly facilitatedby carefully noting position of thumb and in-dex finger (Fig. 8). Thus accuracy of result,simplicity of operation and the saving of muchvaluable time is invariably 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-
Size: 1572px × 1589px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, bookidrefractionmu, bookyear1921
