Prevalence of photosensitivity--an Indian experience.

One thousand nine hundred and forty newly recruited entrants for training as pilots (Group A) underwent photic stimulation during EEG recording during the entrance examination to the flying stream. One hundred and sixty individuals (Group B) working on radars for prolonged periods were interviewed for eliciting complaints referable to photosensitivity and were subjected to EEG. EEGs in respect to 1000 cases (Group C) of known epilepsy were examined for the incidence of a photosensitive response. The study has revealed that 14 cases (0.72%) in group A had an abnormal response to photic stimulation out of which one case developed seizure during EEG recording. One case (0.62%) in group B and 30 cases (3%) in group C were detected to have photosensitivity. The maximum response was seen at 20 Hz stimulation. The prevalence of photosensitivity and its manifestations in these groups indicates that this condition is not uncommon.