[Delay of retinal fluorescence as a death criterion]

Retinal fluoroscopy with measurement of the arm to retina circulation time can be used to evaluate the blood supply to the brain. When the brain tissue suffers from ischaemia as a result of circulatory failure, the arm to retina circulation time will be prolonged. Sixteen patients in deep coma resulting from serious cerebral disease were examined to verify cerebral ischaemia. The results of retinal fluoroscopy and cerebral angiography agreed. We find that retinal fluoroscopy is a simple and reliable method that can be used to detect brain death in comatose patients treated by automatic ventilation. We conclude that the main cerebral circulation can be regarded as occluded if the retinal fluorescence does not appear within 25 seconds after antecubital intravenous injection of fluoresceine. We suggest that the arm to retina circulation time exceeding 25 seconds may be used as a criterion of death.