Rigidity of Construction
Illustration on following page ([Fig. 11a]) shows the reinforced double bearing arms which hold the Ski-optometer lens batteries at two points. This eliminates possibility of the instrument getting out of alignment, and prevents wabbling or loose working parts.
The broad horizontal slides shown in the cut, move in and out independently so that the pupillary distance is obtained for each eye separately by turning the pinioned handle on either side of the instrument. The scale denotes in millimeters the P.D. from the median line of the nose outward, the total of both scales being the patient’s pupillary distance.
[Fig. 11a] also serves to show the staunch construction of the base of the Ski-optometer.
Fig. 11a—Showing staunch construction of Ski-optometer base.
How to Place the Ski-optometer in Position
The patient should be placed in a comfortable position with “chin up,” as though looking at a distant object. The instrument should then be raised or lowered by the adjustable ratchet wheel of the bracket. The wall bracket gives best results when suspended from the wall, back of the patient, as shown on [page 135]. This bracket should be placed about ten inches above the head of the average patient. When the Ski-optometer is placed in position for use, its lower edge will barely touch the patient’s cheeks. It is sometimes advisable to request the patient to lightly press toward the face the horizontal bar supporting the instrument. Particularly good results are secured where a chair with a head-rest is employed in conjunction with the Ski-optometer. (See illustration of Model Refraction Room, [Page 112]).
Cleaning the Lenses
The time-waste of perpetually cleaning lenses is overcome where the Ski-optometer is employed. For the convenience of the operator and protection of Ski-optometer lenses, the latter are concealed in a dust-proof cell, overcoming all dust and finger-print annoyances. When not in use, the instrument should be covered with the standardized hood forming part of the equipment.