A machine-implemented method includes obtaining input data and generating output data. The status of at least one contextual factor is determined and compared with a standard. If the status meets the standard, a transformation is applied to the output data. The output data is then outputted to the viewer. Through design and/or selection of contextual factors, standards, and transformations, output data may be selectively outputted to viewers in a context-suitable fashion, e.g. on a head mounted display the viewer's central vision may be left unobstructed while the viewer walks, drives, etc. An apparatus includes at least one sensor that senses a contextual factor. A processor determines the status of the contextual factor, determines if the status meets a standard, generates output data, and applies a transformation to the output data if the status meets the standard. A display outputs the output data to the viewer.