A method and a computer system and its components for providing spectacles adapted to a future wearer. The method comprises the steps of: inputting in a computer system a first set of data (F1) related to the wearer, comprising at least a prescription of the wearer, inputting in the computer system a second set of data (F2) related to a spectacle frame chosen by the wearer. The computer system is provided with processing means for outputting, on the basis of the first and second sets of data, at least one set of data (S1, S2, . . . , SN) characterizing a pair of ophthalmic lenses adapted to the wearer and the chosen frame.