We conduct a discussion on the problem of 3D-reconstruction by calibrated photometric stereo, when the surface of interest is embedded in a refractive medium. We explore the changes refraction induces on the problem geometry (surface and normal parameterization), and we put forward a complete image formation model accounting for refracted lighting directions, change of light density and Fresnel coefficients. We further show that as long as the camera is orthographic, lighting is directional and the interface is planar, it is easy to adapt classic methods to take into account the geometric and photometric changes induced by refraction. Moreover, we show on both simulated and real-world experiments that incorporating these modifications of PS methods drastically improves the accuracy of the 3D-reconstruction.