Built to Last a Lifetime
Fig. 12—(A. and B.)—This unique, patented split-spring device of screwless construction, securely holds all movable parts. In case of repair, they may be removed with the blade of a knife.
The Ski-optometer is built on the plan of ¹/₁₀₀₀″, insuring absolute rigidity and accuracy and a lifetime of endurance. Particular and detailed attention has been given to the novel means of eliminating screws which either bind, create friction or continually work loose, causing false indications of findings on scales of measurements; hence correct and accurate indications are insured in the Ski-optometer by means of a split-spring washer construction similar to that of an automobile tire’s detachable rim ([Fig. 12]).
This patented spring washer construction securely holds the phorometer lenses, the rotary prism and the revolving cylinder lens cells.
Whenever necessary, or in case of repair, these parts may be readily removed with the blade of a knife.
Chapter V
CONDENSED PROCEDURE FOR MAKING
SPHERE AND CYLINDER TEST
WITH THE SKI-OPTOMETER
Notwithstanding various methods employed, for both subjective and objective refraction, the following synopsis of the previous chapters will unquestionably prove most valuable to the busy refractionist, enabling him to make error-proof examinations in practically every case without resorting to the transference of trial-case sphere or cylinder lenses. A careful reading of chapters one and two should be made however, so that one may gain an understanding as to how spheres and cylinders are obtained with the Ski-optometer.