Measurement of the optical density of the optic nerve head II: short-time fluctuations of the optical density of the nerve head.

The fluctuation of pallor with increasing IOP could be due to either insufficient reliability of the method or to an unrecognized pulsating phenomenon. A better arrangement should eliminate imperfection of the method. Coupling the release with the ECG should reveal a relationship to the arterial pulse rate. Neither condition could be demonstrated as the reason for the fluctuation. The connection of the fluctuation and its possible relationship to central venous pressure is discussed. The margin of error is shown, which is 9% on average.