Visual cortical prostheses (VCPs) may be useful for many individuals with acquired blindness. VCP stimulation of a point on the visual cortex elicits the perception of a flash of light, known as a phosphene; however, phosphenes resulting from concurrent stimulation of multiple points on the visual cortex do not combine into a coherent shape. Here, the authors used a dynamic pattern of stimulation known as current steering, whereby the sequential delivery of current via two electrodes in turn leads to the formation of a ‘virtual electrode’ between them — resulting in perception of a line. Such stimulation led to the perception of letters by sighted and blind participants.