Fundus Photography of Width and Intensity Profiles of the Blood Column and the Light Reflex in Retinal Vessels

Abstract Various optical properties of the fundus camera may have important implications regarding the use of photographs for image size measurements. By scanning across retinal vessels with a microdensitometer the width and the intensity characteristics of both the central light reflex and the streaming blood column may be measured. To establish a reliable basis for future measurements, we analysed the retina‐to‐film magnification, possible aberrations and the resolving power of our Zeiss camera. Furthermore, fundus photography was performed in 100 young men, and the necessary level of accuracy in focusing the camera was established. We also investigated the effects of various amounts of defocusing on width and intensity readings from densitometric scans across retinal vessels.