Opera glasses are some of the oldest binocular designs, dating back to the early days of opera, where opera-goers seated in the rear of an opera hall or in one the balconies or boxes wanted a close-up view of the performers and stage scenery. The original intent was to supply something small, unobtrusive, yet elegant and stylish. This remains the intended use for theater glasses to this day, though you can use opera glasses for other applications calling for a small, low power optical instrument. How are opera glasses different than a regular binocular? There are several differences, both internal and external.