Multifunctional apparatus and instruments, with a screen, for measuring various parameters for spectacle lenses, including spectacle frame shape and size, the eye position in the frame and the wearer's visual behaviour, in particular by detecting and measuring eye and head movements in response to visual stimuli; multifunctional apparatus and instruments, with a screen, for photography and/or video recording and display of the spectacle frame wearer's image and printing the image, in order to help the choice of frames; multifunctional apparatus and instruments, with a screen, in particular for opticians' shops and optical stores, for displaying animations, information and advertisements and comprising software dedicated to support the sale of spectacle lenses and/or frames by way of demonstrations and simulations