Topical measurement of fundus pulsations

An instrument suitable for fundus pulsation measurements at preselected points of the retina is developed. Fundus pulsations are measured with a laser interferometer using a single-mode laser diode. Part of the laser light is reflected from the front side of the cornea and part of it is reflected from the retina. The interferences produced by the two remitted waves are detected with a linear CCD array. Evaluation of the interferogram yields the time course of the fundus pulsations. This laser interferometer is coupled to a fundus camera. The setup enables real-time inspection of the laser spot on the fundus. Measurements on seven healthy young subjects are presented. Fundus pulsations in the macular region are significantly smaller than those in the optical disk, but significantly larger than those in peripheral regions of the retina. The association between our results and the subretinal vasculature is discussed and possible future applications of our method are presented.