During the 17th and 18th century “optics” (in the broadest sense of the word) became a very popular subject. It was discussed – scientifically as well as philosophically – in the academic circles of Paris, Vienna and – last but not least – Venice, where the old “state university” of Padua could boast of important discoveries in this field. For instance, in ophthalmology (up to that time a minor, nearly despised working field for surgeons), a famous department was established in 1785. As most notably witnessed by Casanova, in enlightened literary salons from Paris to Naples, a fascinated lay public started discussing glasses, microscopes, telescopes, magnifying glasses, mirror-tricks and, with increasing eagerness, the anatomy and physiology of the eye. In a more superficial way (but no less passionately!), admirers of the “opera lirica” became attracted to the increasing sophistication of opera glasses. The so-called polemoscope (“lunette de jalousie”) – today forgotten but in a certain way immortalized by a short comedy of Casanova (1791) – made it possible to secretly observe one`s (female?) theatre neighbour thanks to the (invisible) deflection of the beam path within the binoculars. In the academies which emerged in many Italian towns in the 17th and 18th century, the philosophical question “What is seeing?” was associated with exponents of “sensualism” like David Hume and John Locke, whose influence was enormous. Also theological theories, based on old Platonic influences, were reiterated and newly elaborated. The rise of the camera obscura (in earlier times a kind of luxury toy for nobles) influenced contemporary painting in Venice (Canaletto, Carlevarijs, Bellotto). The paper intends to present an overview of different social, scientific and medical aspects of the “culture of the eye” in Venice and other European centres during the Enlightenment period.