A sliding bridge eyeglass frame provides salespersons and customers the ability to insure that a proper interpupillary distance between telescope oculars is achieved during a fitting session. The demonstration frame device of the present invention includes first and second bridge portions which are slidably and reversibly fixedly attached to thus allow a customized fitting for particular customers. Once proper interpupillary distances are achieved, the first and second frame members are secured together such that proper dimensions and configurations can be obtained for production of a final product.