• The Man Who Almost Invented the Ophthalmoscope

    If the name, Charles Babbage, means anything to you, it is most likely within the context of his pioneering contributions to the history of computer science. It is less well known that he also invented the ophthalmoscope. Or, at least, he almost did. 

    Babbage was born in Devonshire, England, around 1791 to the family of a well-to-do banker, who emphasized early education for his children. As a result, when the young man entered Cambridge in 1810, he knew more mathematics than his university tutor and, by 1828, had become the Lucasian Professor of Mathematics at Cambridge (a chair once held by Isaac Newton). However, teaching seemed to be neither his strength nor his passion (he apparently never gave a lecture), and he resigned from his position in 1839 in order to devote all his time to his true calling as a mathematician and an inventor.

    His interests and inventions were eclectic, ranging from a cowcatcher for locomotives to actuarial theories and tables. The biggest problem he sought to address, however, was that mathematical tables of the day, which were key to navigation, science, engineering and mathematics, were all calculated by hand, which led to frequent errors in transcription and calculations. Babbage reasoned that these human errors could be overcome by mechanization, which led to his formulating the concept of mechanical computation. 

    His first attempt at a computer began in 1822 with a “difference engine,” which was intended to automatically compute values of polynomial functions. The device was mechanical and unwieldy (if finished, it would have approximately 25,000 parts and weigh 15 tons), but the basic architecture was similar to modern computers. With various colleagues, he labored for more than a decade, exhausting much of his personal wealth, as well as public funding. He achieved some success with a steam-powered device, demonstrating that calculations could be mechanized, but government confidence and support finally ran out, and he never completed his difference engine.

    He did not give up on the concept, however. In later life, he designed an “analytic engine,” which was more complex than his difference engine and represented a transition from mechanized arithmetic to full-fledged general purpose calculations. It was programmed with punched cards and used several features that are found in modern computers. It was never completed, but he tinkered with it until his death in 1871. In 1991, a team of British researchers completed construction of Babbage’s difference engine from his original plans and showed that it worked. Babbage’s interest in the eye stemmed from his affliction with bilateral monocular diplopia, which he was able to partially correct with the use of a pinhole or a concave lens. His study of the eye led him to design a device for viewing the posterior aspect of the globe.

    Although no model or drawings apparently exist, it has been described as consisting of a tube with a mirror that was angled to reflect external light into the eye. There was a central opening in the mirror (silver removed) through which the observer could view the internal ocular anatomy. In 1847, Babbage presented his idea to the distinguished British ophthalmologist and physiologist, Thomas Wharton Jones, who was apparently unimpressed and offered no encouragement to the inventor. And that was where it ended, until about seven years later, when the German physicist, anatomist and physiologist, Hermann Helmholtz, described a somewhat similar device, and the rest is history.

    Jones admitted his error by acknowledging Babbage’s contribution in an 1854 article in “British and Foreign Medico-Chirurgical Review,” and Babbage included it as one of his accomplishments in his 1864 autobiography. Although he lost his chance to be included in the pantheon of ophthalmic history, he is considered by many to be a father of modern computer science. In 2011, a team of British researchers began attempting to build Babbage’s analytical engine, despite lacking the complete original design, and hope to have it finished by 2021, in time for the 150th anniversary of the inventor’s death.

    For more stories from Scope, download the summer Scope 2016 [PDF].