Keystone Model 40 Comfort Eye Stereoscope
United States, 1930s
In the 1930s, Keystone started a stereo-optical department for “the development of skillful and comfortable vision.” They produced a number of stereoscopes to be used with special eye training stereoviews that were available by prescription only. The stereoviews exercise one’s eyes when the user shifts focus between different numbered markers on the cards. Keystone claimed, “The human body is benefitted by proper exercise. The eyes are no exception.”
We also have a Model 40 with an easel and a Model 50 in our collection.
Provenance