HIGH speed photography affords the use of a new technic in photographing the external eye. The essential feature of the unit consists of an electrical flash tube developed by Edgerton.1 The illumination afforded is extremely brilliant (about 42,000,000 lumens) and of very short duration (0.001 second) and produces no discomfort to the patient. From a single tube 10,000 or more light flashes can be obtained. There is no appreciable sense of heat to the patient, even when the light is placed as close as 4 inches (10 cm.) from the eye. The after-image produced is inconsequential.
A slender glass tube measuring about 3 inches (7.5 cm.) in height and filled with xenon gas is used. When the electric charge is released from a power pack, ionization of the gas results and a brilliant flash is produced. The quality of the light is uniform and substantially correct for daylight color