Charles Babbage 1791-1971

c1847

Babbage’s “ophthalmoscope” is the story of what might have been if…….

His invention was three years before Hermann von Helmholtz discovered what he called his eye speculum or ophthalmoscope in 1850.

No model has been found of Babbage’s instrument. The reconstruction shown here is based on a description given by Thomas Wharton Jones, an ophthalmologist who tried to use it in 1847.

Babbage used a plane mirror with two or three scrapings of the silver coating removed from the centre. The mirror was mounted in a tube at 45 degrees with the side of the tube open to receive light from an external source.

Wharton Jones was unfortunately a high myope (minus 6D) and dismissed the instrument as ineffective. It was abandoned by Babbage who moved on to his analytical engine. The tragedy was that William Cummings worked at the London Ophthalmic Hospital, Moorfields at same time only 4k away. Cummings, who was emmetropic, had published of the diagnostic value of light being reflected from the eye and would have had little difficulty in recognising the value of Babbage’s invention.