Today the U.S. Patent and Trademark Office officially granted Apple a patent that relates to optical systems, and, more particularly, to Apple's future smartglasses with tunable lenses. With today's Apple Vision Pro, additional Zeiss prescription lenses could cost users approximately US$600 a pair, according to Bloomberg's Mark Gurman. With Apple's future smartglasses, they'll use an advanced adjustable lens system that, more than likely, not carry an added cost.