Quantification and calibration of flash stimuli in clinical research

Despite the relatively wide use of flash-type stimuli in VEP studies, no universally accepted standards or methods of measurement for these stimuli are in existence. Several methods have been described for the determination of flash-intensities, however, the majority of these methods are not sufficiently rigorous, or are based on overly optimistic assumptions on the ideal nature of flash-stimulators. We describe here a simple method for the determination of flash-stimulus energies and absolute peak intensities. Our method does not require specialized optometric instrumentation, and should be readily adaptable to any modern laboratory.