Abstract: A method, a device, and a computer program product for determining a refractive error of an eye of a user are disclosed, as well as a method for producing a spectacle lens. The method for determining includes: displaying an image with a spatial modulation to the user; optionally, recording a reaction of the user to a variation of the spatial modulation over time; detecting a point in time at which a perception threshold of the user is reached; and determining the refractive error of the user from the spatial modulation, wherein the image contains a source image with several picture elements, wherein values for an image parameter are assigned to the picture elements, and wherein the spatial modulation is generated such that the values of the image parameter determine the values of a modulation parameter of the spatial modulation in the image.

Abstract: The invention concerns the insulation of a duct 2, especially an air-conditioning or ventilation duct, which passes through a penetration in a wall 1 or ceiling or the like, and an insulating material 3 is provided all around the outside of the duct 2. In this regard, the insulating material 3 has an end face pointing at least partly in the direction of the penetration. Sections of the end face, at least, are provided with heat-resistant adhesive material 11.