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Who Invented Bifocals?


US statesman Benjamin Franklin has long been credited with the invention of bifocal spectacle lenses, but whether this is historically accurate or merely a myth is a matter of debate. Most serious historians now agree that the hard evidence is lacking.

Benjamin Franklin, writer, politician, scientist and optician, was a great advocate of air bathing and is known to have favoured sitting naked each morning before an open window. Presumably he did not curtail this activity while lodging at what is now number 36 Craven Street (a few doors down from the present College of Optometrists' headquarters) between 1757 and 1775.

Franklin can still be seen in the street (fully clothed) in this oil painting by royal academician Stephen Elmer, dated 1777. The portrait was acquired by the Museum in 1939. A subsequent copy of the painting is also on display at the US Embassy building in Paris.

Franklin is known to have worn temple spectacles after his arrival in England, as must have done other members of his family. In February 1757 he wrote to his wife Deborah Franklin to describe the new furnishings in his Craven Street lodgings:  'Look at the figures on the China Bowl and Coffee Cups, with your spectacles on; they will bear examining'. In this painting, however, he is shown wearing silver folding nose spectacles, a precursor of pince-nez, but the College's interest in this portrait stems not from the eyewear depicted, but from the claim that Franklin was the inventor of the split-bifocal lens.

The idea of a split lens, for use as a trial lens rather than for spectacles, had been suggested by Zahn in 1683 and, again, by Hertel in 1716, but there is no evidence that such lenses served a practical, ophthalmic function until several decades later. 

Franklin wore spectacles continually after 1776. He admitted in 1784 that without them he could not 'distinguish a letter even of large print'.

In 1779, whilst on his diplomatic mission to France which lasted from 1777-1785, Franklin had ordered a pair of spectacles from the English optician, Sykes, who had a business on the Place du Palais-Royale. The fact that Sykes wrote to Franklin explaining that his spectacles had been delayed due to the lenses having broken three times during cutting has been taken as evidence that the ambassador was ordering something out of the ordinary. The price of 18F, which he paid for the spectacles, was certainly higher than was usual at the time. 

In a letter of August 1784, written to his friend George Whatley, Franklin declared himself 'happy in the invention of double spectacles, which serving for distant objects as well as near ones, make my eyes as useful to me as ever they were'. It should be noted that he did not describe them as 'my' invention, nor should the wording be taken necessarily to mean that the invention was recent.

Whatley replied, referring to the spectacles as 'your invention' and as something he had been discussing with the English optician, Peter Dollond. The Dollonds were, it seems, producing spectacles of this, or a similar, type, as a bespoke service, but were not convinced that the idea had commercial potential.  

Bifocal spectacles were described in a further letter of Franklin's to Whatley, dated 23 May 1785. In this he again referred to 'my double spectacles'  (where 'my' need only signify ownership) and provided a sketch. The letter continued: 'The same convexity of glass, through which a man sees clearest and best at the distance proper for reading, is not the best for greater distances. I therefore had formerly two pair of spectacles, which I shifted occasionally, as in travelling I sometimes read, and often wanted to regard the prospects. Finding this change troublesome, and not always sufficiently ready, I had the glasses cut and half of each kind associated in the same circle. By this means, as I wear my spectacles constantly, I have only to move my eyes up or down, as I want to see distinctly far or near, the proper glasses being always ready.'  

Some historians, however, have suggested that in this letter to Whatley, Franklin refers to an experiment carried out more than 20 years earlier in London. A letter from the newspaper editor, John Fenno, to his wife dated 8 March 1789, supports this theory. In it Fenno describes a meeting with Franklin in which the elderly statesman had mentioned wearing the spectacles over many years: 'He informed me that he had worn spectacles for 50 years; each eye appeared to be formed of two pieces of glass divided horizontally - he informed me that he had always worn such'. 

The Fenno letter also fits in with the fact that Franklin suffered from hyperopia, requiring spectacles for this condition as early as the 1730s. This would have made him likely to have benefited from bifocals by the time he arrived in London in 1757.

Before leaving the America the first time Franklin had clearly had an interest in optical developments. He imported vision aids and advertised 'spectacles of several sorts' in the Pennsylvania Gazette. Our knowledge that he was involved in the supply of spectacles in his early adult life may cause us to consider that he may well have had the interest to experiment with bifocals at an earlier date. 

Yet the only portrait of Franklin in which he is depicted wearing bifocals is one by Charles Willson Peale, dated 1785, when the old man was aged 81 and living once again in Pennsylvania. This does at least suggest that we would be right to say that Franklin introduced bifocals to America. Wider public awareness of the invention only came about in the early 1790s, following Franklin's death.

During this period several authors published the Whatley letter, thereby cementing in the public mind the link between bifocals and Franklin. Peale, having painted Franklin wearing bifocals, is known to have made his own pair in 1788 and may have been responsible for introducing the concept to the first US optician, John McAllister, some time after 1799. 

The idea for bifocal spectacles, attributed by some people to Franklin in both Britain and the US, (though never patented by him or anyone else) soon led to further developments. The use of hinged supplementary visors (to hold reading lenses) was patented in London by John Richardson in 1797. By 1836 Isaac Schnaitman, a German immigrant to Philadelphia, had taken out a patent on one-piece lenses with both distance and reading portions ground on to one piece of glass.

Another claimant to the title?

Benjamin West (1738-1820), an American artist, originally from Philadelphia was a natural friend for Franklin in London. He woul;d later become President of the Royal Academy from 1792-1815. West is known to have been an early wearer of 'divided glasses' or bifocals, possibly before 1800, but probably not before Franklin. That has not stopped historians pushing the claim of West or his predecessor at the Royal Academy, Sir Joshua Reynolds, to have 'invented' bifocals in the 1760s.

Why anyone should be so determined to attribute their invention to a prominent named individual is perhaps the more baffling question.

 It does seem likely, however, that these men, especially West, were using split lenses supplied by London opticians for artistic purposes, if not for normal vision, and that this may have prompted Franklin to order some.

The Definitive Word...for now 

Unless further evidence emerges all we can say for certain is that Franklin was one of the first people to wear split bifocals and this act of wearing them caused his name to be associated with the type from an early date. This no doubt contributed greatly to their popularisation. The evidence implies, however, that when he sought to order lenses of this type the London opticians were already familiar with them. Other members of Franklin's circle of British friends may have worn them even earlier, from the 1760s, but it is at best uncertain (and arguably improbable?) that split bifocal lenses had a famous gentleman inventor.

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