Ophthalmoscope

This well-used instrument, still in its original velvet-lined case, has probably looked into countless eyes; it is still recognizable today to anyone who has had an eye exam. A clear view of the fundus, or back of the eyeball, allows doctors to look directly at the retina, blood vessels, nerves, and other structures of the eye and check for signs of disease. Before the invention of the ophthalmoscope, physicians had observed that the eyes of animals seemed to glow with light under certain conditions. Some argued that the eyeball produced its own light like a firefly, generating electricity, or perhaps re-emitting light that it had absorbed during the day. The correct answer—that this light was reflected from outside the eyeball—meant that if a focused view of this reflection could be obtained, the inside of the living eye could be observed directly. In 1851 at age 29, physician Hermann von Helmholtz solved this challenge by inventing a working ophthalmoscope. He called his invention the Augenspeigel, or eye-mirror. Despite its name, it used tilted glass plates to reflect light into the eye, although later models adopted mirrors for this purpose, and “ophthalmoscope” (eye viewer) became the accepted term. Edward Loring, who in 1869 invented the model of ophthalmoscope seen here, never stopped tinkering with and improving his invention. In his 1892 Textbook of Ophthalmology, he expresses his enthusiasm for this wonderful device: “In the whole history of medicine there is no more beautiful episode than the invention of the ophthalmoscope, and physiology has few greater triumphs.” The ophthalmoscope has been the delight of many other inventive physicians and technicians, who for more than 164 years have eagerly incorporated new ideas and new technology—electric bulbs, batteries, new lenses and mirrors—into hundreds of different ophthalmoscope models