Recognition of papilledema as a sign of increased intracranial pressure awaited the invention of the ophthalmoscope by Hermann von Helmholtz and the fundus observations of Albrecht von Graefe. Although the luminescence of the pupils of certain animals was noted as early as Roman times, the first direct observation of the optic nerve and retinal vessels was not reported in the medical literature until 1704. This was accomplished by Jean Mery when he held a cat under water until the anoxia dilated the pupil of the cat; the optical effect created by the water unexpectedly revealed the optic nerve and retinal vessels. This experiment, obviously, could not be performed on humans; demonstration of the luminescent quality of human eyes was finally achieved in 1846 by William Cummings.

The first primitive ophthalmoscope was developed in 1847 by Charles Babbage, who did not grasp its clinical significance. Babbage's paper describing his work, "About the Light of the Eyes," was read by a friend, DuBois Raymond, on December 6, 1850, before the German Physical Society. The only written report on Babbage's discovery was in 1854 by an English ophthalmologist, who discouraged him from continuing his work. The importance of this discovery, however, did not escape von Helmholtz, then a young professor, who developed the first clinically practical ophthalmoscope in 1851.

During the next decade, many reports of retinal signs were published. In 1860 von Graefe reported his observations in four patients with brain tumor and a swelling of the optic nerve head; he called the observation stauungspapille. Parsons coined the English term papilledema in 1908. Von Grade's con-clusion about what he saw was correct. It was indeed fortunate for all of ophthalmology that all four cases reported by von Graefe were brain tumors. He did not recognize in his first report the broad differential diagnosis of a swollen nerve head, It remained for Paton and Holmes In their paper in 1911 to differentiate between papilledema with increased intracranial pressure and optic neuritis. Their basic differentiation was based on visual function. Edema of the nerve head with decreased vision was considered optic neuritis; edema of the nerve head without decreased vision was papilledema secondary to increased intracranial pressure. As experience has taught us, decreased vision also occurs as a result of chronic papilledema secondary to increased intracranial pressure and subsequent optic nerve atrophy.

After the initial observations of those early pioneers, the use of the retinal examination spread rapidly in all branches of medicine. Hughlings Jackson said, "I think it is the luckiest thing in my medical life, that I began the scientific study of my profession in an ophthalmic hospital." In his lectures, Charcot often referred to the use of the ophthalmoscope. "Gentlemen," he once said, "I could not too strongly recommend to you to seek in the application of the Helmholtz mirror the invaluable assistance which it is capable of yielding."