Retinal Circulation in Diabetes Mellitus

Our present knowledge of retinal circulation can be traced to Germany in the middle and late 1800s. During those years, Hermann von Helmholtz, the inventor of the ophthalmoscope,¹was professor of physiology at Königsberg University, and Theodore Leber,²who performed the definitive studies of the anatomy of the vasculature of the eye, was professor of physiology and ophthalmology at Heidelberg University. Thus, beginning in the 1900s, researchers could see retinal circulation in the living eye and were armed with precise knowledge of its morphology. (Even today some contend that the Englishman Charles Babbage invented the ophthalmoscope, although he published nothing about it. It is difficult to give credit to an individual for secret research.)³Progress, however, was slow because while the retinal blood vessels could be seen, they were buried 2.5 cm from the surface in one of the most delicate tissues of See also p 991.