DeZeng Phoropter 1922
This was one of the early ways of putting many lenses together in a convenient way in order to do a refraction exam (determination of glasses power) on someone. There is a good YouTube presentation about phoropters here
This was one of the early ways of putting many lenses together in a convenient way in order to do a refraction exam (determination of glasses power) on someone. There is a good YouTube presentation about phoropters here