We show how ICC profiles can be used to handle a variety of transforms intended to either simulate the appearance of a colour image to an observer with a colour vision deficiency (CVD), or adjust the image to improve the discriminability of colours to the CVD observer. In ICC v4, the different profile classes transform between a data encoding and the ICC Profile Connection Space (with the exception of the DeviceLink profile, which is a transform between two data encodings). Some simulation and Daltonization algorithms can be concatenated into a single matrix, which can be encoded as a v4 LUT-based profile or a matrix/curve profile. Alternatively a more complex transform can be encoded in the colour look-up table in a LUT-based profile. The new iccMAX architecture provides some additional possibilities, such as parameterized transforms for individual observers, encoding of functional transforms in the MPE and Calc elements, and the use of custom colorimetric observer and profile connection space. By using the ability to connect spectral data, iccMAX profiles also enable computation of the spectral response of the CVD observer to a given spectral reflectance, light source or emission.