German physician Hermann von Helmholtz, who devoted much of his career to studying the eye and the physics of vision and perception, demonstrates his ophthalmoscope to the Berlin Physical Society. The invention revolutionizes ophthalmology.
Although von Helmholtz was not the first person to develop an ophthalmoscope nor the first to examine the interior of the eye, his device was the first to really be put to practical use.
The ophthalmoscope allows the examining doctor to look inside the patient’s eye at the lens, retina, and optic nerve. It is the indispensable tool for diagnosing diseases of the eye, including glaucoma, and is used to screen for diabetic retinopathy, a condition in diabetics that can result in blindness. Caught early enough—and the ophthalmoscope is the method for pinning it down—the condition can be treated with laser surgery. The ophthalmoscopes most of us grew up seeing at the eye doctor’s office are still in use as a basic diagnostic tool. For more complicated procedures, scanning laser ophthalmoscopy is available.
While the ophthalmoscope made von Helmholtz famous, he distinguished himself in a number of scientific disciplines. He measured the speed at which the nerves carry signals and wrote fundamental textbooks on physiological optics. Moving from sight to sound, he wrote on acoustics and the physiological perception of tone as the basis of musical theory.
He also contributed to the theory espousing the heat death of the universe as a necessary consequence of ever-increasing entropy. The Encyclopaedia Britannica wrote: “His life from first to last was one of devotion to science, and he must be accounted, on intellectual grounds, as one of the foremost men of the 19th century.”—TL