Although optical pulsar studies have been limited to a few favoured objects, the observation of pulsars at optical wavelengths provides an opportunity to derive a number of important pulsar characteristics, including the energy spectrum of the emitting electrons and the geometry of the emission zone. These parameters will be vital for a comprehensive model of pulsar emission mechanisms. Observations of the Crab pulsar with the high-time-resolution photon-tagging photometer IquEYE show an optical–radio delay of ~178 μs. Incorporating simultaneous Jodrell Bank radio observations suggested a correlation between giant radio pulses and enhanced optical pulses for this pulsar, thus offering possible evidence for the reprocessing of radio photons.