Abstract: Method and arrangement for performing measurements of the topography of a surface (20), such as topography of an eye surface (20), wherein projecting means (1, 12) for projecting an image onto said surface (20) comprises a projection light source (1), and wherein at least a fraction of light leaving the surface (20) as a result of said projection is received using one or more receiving units (31, 32), such as charged coupled device (CCD) based cameras. The topography of the surface (20) is determined by analysis of said fraction of light leaving the surface (20), due to thermal emmission and the image projected onto the surface (20) is projected with light comprising a colour for which the surface (20) is opaque, such as infrared light.