Keystone Correct-Eye-Scope | Model 40 Comfort Eye Stereoscope

United States, 1930s

Starting in the late 1800s, the Keystone View Company produced hundreds of thousands of stereoviews for general use. It wasn’t until the 1930s that they started a robust stereo-optical department that created viewers and stereoviews for “the development of skillful and comfortable vision.” This particular unit features an adjustable easel combined with the Model 40 Comfort Eye Stereoscope that has a printed scale. The device was used with special eye training stereoviews that were available by prescription only and recommended for use only upon a doctor’s instruction. Keystone promoted the unit claiming: “The human body is benefitted by proper exercise. The eyes are no exception.” The unit can also be used for viewing general purpose stereoviews.