To understand the technology of Progressive Multifocal lenses, its critical to understand the evolution of eyewear technology throughout history. This will serve greatly to demystify lens and progressive technology.
3000 BCE: The first “lenses” were crystals, gems, and glass or “burning glass” used to start fires, which were recorded in an ancient Assyria poem written about 2000 BCE. Ancient crystal lenses exist from both Assyria and Crete that appear to have non-decorative purposes, probably used as fire starters. The Egyptians used back-painted glass or crystal to create human-like eyes to adorn sculptures and sarcophagi that were essentially lenses in their basic form.* Eyes that seemed to follow you around the room must have creeped out the entire Egyptian empire.
2000 BCE: Egyptian hieroglyphs show ancient glass-blowing.
350 BCE: Aristotle identifies that a rainbow is from the refraction rain drops, and also mentions the defects of myopia and presbyopia.
250 BCE: Ptomely of Egypt creates tables of refraction, and correctly identifies the refractive index of water at 1.33.
70: Roman philosopher Seneca notes that objects viewed through a water filled glass globe are enlarged and distinct.
1021: The seven-volume Book of Optics by Ibn Al-Haytham written from 1011 to 1021 CE in Cairo Egypt changed the world. Ibn Al-Haytham was the Leonardo Da Vinci of his era, and like Da Vinci he was an utter polymath and incompressible genius. His work was the cornerstone to the science of Optics, but was also crucial to the formations of the scientific method, and contributed tremendously to the fields of medicine, physiology and physics. His writings were translated into Latin surprisingly quickly and shared by scholarly monks all over Europe. His empirical thought influenced early Universities, the Italian Renaissance, and possibly even the modern era. Many of his scientific observations were centuries ahead of similar European “discoveries”. Among his many contributions are the mathematical foundation to optics and identifying how using two eyes we see one image.
It’s impossible to list all his accomplishments, but his critical one for this discussion was his idea it was possible to correct refractive errors by using lenses, although there is no evidence he attempted this himself. Although today Optics as science is kind of back-water (there is only one PhD Optics program in the US) originally it was both the first scientific field, and the scientific field that unites both medicine and physics.
Circa 1000-1100s: Visby Lenses: On the Viking island of Gotland in Sweden, there was a lens-making industry using highly polished quartz crystals. A few samples are of extremely advanced and precise bi-aspheric curvatures which were not matched until the early 20th century. Their purpose is unknown to us today but fire starters is the leading candidate. They were both brilliantly and carefully manufactured by someone with advanced knowledge of optics, probably acquired through testing and observation. Lots of questions remain, and they are sort of outliers, but Visby lenses demonstrate methods of manufacturing highly polished and accurate lenses were known in this era.
Circa 1130s: Increasingly larger Gothic cathedrals employed rib-vaults and flying buttresses to create lighter and more open spaces, and to fill that space began employ stain-glass windows because light was associated with the power and presence of God. Cities subtlety competed to have the largest most ornate church buildings. More complex and even larger stain-glass windows exploded in popularity by the 1200s as they became a tool to communicate biblical stories to mostly illiterate parishioners and attract lucrative pilgrims. As cathedral building boomed all over Europe and stained-glass windows grew in size and complexity, a glass industry rose up to meet the need.
1221: Glassblower’s guild is formed in Venice.
1240s: The beautiful and advanced glass technology of the Egyptians, Romans and Mesopotamians was lost with the decline of the Roman empire around 200 CE. It would take almost a thousand years to recover! The dark ages were literally darker than we imagine. The demand for beautiful stained-glass windows skyrocketed in the exciting heyday of the Middle Ages. The Venetians’ responded by combining local re-discoveries with technology borrowed from the Byzantine Empire and made a valiant and full recovery of Roman glass technology around 1240. The glass-making industry in Venice quickly became so important to the economy that the emigration of glassmakers was prohibited.
1268: English Monk and Scientist Roger Bacon created the first magnifying glass used to better examine small objects, probably using a “burning glass”. While living in Paris, he wrote Opus Majus which referenced, built on, and then expanded Al-Haytham’s writings on Optics. Although he never mentions igniting wayward ants and was not the first to discover a lens could magnify objects, he was the first to put that quality of lenses to practical use for both reading and science… and then write about it. He was a prolific and influential scientific author, and his works were quickly shared among monasteries throughout Europe with a lasting impact in many fields, including Optics.
1280s: The first pair of spectacles was probably made by an unknown monk in Pisa in Tuscany in the 1280s who intended to keep his invention secret. Friar Alessandro della Spina is credited for copying this technology and making his secret known to the world. “Spectacles having first been made by someone else, who was unwilling to share them, he [Spina] made them and shared them with everyone”. From the records of the Monastery of St. Catherine in Pisa.* This story is supported by a local sermon from the same era, that also omits the name of the inventor. Although 1285 or 1287 are often cited as the exact date, there is an approximation at best.
1291: As the demand for stained glass increases, Venice moves the rapidly expanding industry of glassmaking to the island of Murano to reduce the effect of devastating fires on the rest of the city. To this very day, Murano remains a premier world center of fine artisan glass and training.
I even own a Murano, by Nissan that is. This is a reflection of Murano’s huge and continuing influence on Western art & culture for over 800 years! You can just say the name Murano and it exudes artistic brilliance and wonder.
1300-1301: In Venice Italy, the guild of crystal workers separates regulations for Lapidees ad Elgendum (magnifying lenses) and Roidi d Ogli (spectacle lenses) in 1300.* The next year in 1301, glass is allowed for the first time for spectacle lenses, not just quartz crystal, but it must be only of the highest quality glass. There was limited availability of whole quartz crystals large enough to be used as eyeglass lenses. Glass at this time wasn’t very clear, but it was available. This was a momentous event in the history of eyewear.
1321: Venice officially changes the name of spectacles to Veri da Ochiali (real glasses) and taxes them at 5%.* The term Ochiali is still used in Italy today for eyeglasses or spectacles.
1326: Spectacles are mentioned in a list of personal items owned by Bishop Walter de Stapledon who co-founded Exeter College in Oxford England with his brother.*
1330s: What we call “crown” glass probably originated in Syria in antiquity. It was glass blown into a globe and then flattened, reheated, and spun into a thinner plate using centrifugal force. The name “crown” comes from the ridged and increasing thicker center section. In Rouen Normandy, a small group of French glassmakers introduced a greatly improve crown glass manufacturing technique enabling a much larger “plate”. All the glass of this era contained imperfections and bubbles, slightly opaque and fairly dull, and was mostly grayish in color.
1380: English author Geoffrey Chaucer mentions spectacles in The Canterberry Tales: “It seems to me that poverty is an eyeglass through which one may see his true friends.”
1384: Customs records in England show that 1,151 pairs of spectacles were imported in July through September of 1384, mostly from Holland and Venice.*
1420s: Woodblock printing was introduced to Europe from Asia using full-page woodcuts to press paper. Combined with more efficient paper manufacturing the price of books was reduced.
1440s: Movable type was invented in China around 1040 by Bi Sheng using ceramic letters, and it would finally make its way to Europe in the early 1400s. The first movable type of printing suffered from thin ink, odd-sized ceramic letters, and slow speed. Johannes Gutenberg did not invent movable type, but he did invent an entirely new system of printing. He invented a superior metal alloy to make letters sharper, durable, and equal in size resulting in much clearer and uniform printing. He also greatly improved the ink formula by making it much darker and thicker. Additionally, he designed a new mechanical press system that made printing much faster, more accurate, and far less expensive. A single press could output 3600 pages a day. Gutenberg’s new printing press, alloy, and ink spread rapidly from Mainz Germany all over the world. By 1485 there were about 50 printers in Germany, Italy, Denmark, and Switzerland.
This really points out the true complexity of inventing. Gutenberg was a genius and polymath to improve so many aspects of printing in one swoop. It might never have taken off had he only improved one or even two elements. This required advanced knowledge of chemistry, metallurgy, and mechanical engineering all working together. He hit a home run, Gutenberg’s printing press is still considered by some to be the most influential invention in human history.
1450: Angelo Brovier in Venice about 1450 invents clear Cristallo glass by using much higher quality ingredients. It was made with carefully chosen pebbles of quartz with less iron, mixed with a very specific type of imported soda ash. It was skimmed and re-mixed, repeated many times in a very long and complicated process to increase the purity. Cristallo was almost perfectly bright and clear in contrast to the grayish, semi-opaque and dull glass of this era.
Cristallo was extremely expensive and while not particularly known to be used in eyewear, it did inspire further technical improvements in glass manufacturing. The less expensive successor to Cristallo was Pebble Glass (and later Brazilian Pebble Glass) due to the fine quartz pebbles used instead of sand. It was used extensively in eyewear and considered optically superior to both crown and flint glass. Because it was harder and more difficult to surface Pebble Glass was a premium glass product and was available in eyewear up to the 1920s.
1499: The Octavio book format is invented in Venice in 1499 by Aldus Manutius & Francesco Griff. All books prior to this were extremely large and had to be read at lectern or table, and were printed in small runs of only about 250. The Octavio was much smaller, used smaller types and far less paper, and as a result, was far less expensive and could be held easily by the hands. Print runs were up to 1000. Venice becomes the center of the book industry in Italy. As the letter type for Octavio books was much smaller more people required spectacles to read them.
Frames: Almost all eyeglass frames of this 1280-1500 era are what we term Rivet Glasses today. Rivet Glasses are like two flat framed magnifying glasses, with small handles joined with a single rivet or nail at the handles, and held with the hands or later using ribbon, cord or leather straps tied around the head. Some paintings depict someone holding a single lens similar to today’s trial lenses but used as a monocle. As a pair, Rivet Glasses could be folded together when not in use and carried in a pocket or case. What we know about eyeglasses of this era is mostly from artwork and writings, as most rivet frames were made of bone, whalebone, wood, tortoiseshell or buffalo horn and have not survived. The oldest artwork depicting spectacles is from 1352, and the oldest surviving pair of spectacles that can be dated accurately is from about 1440.
The 1400s did not see much in the advancement of frames; however, spectacles did drop in price substantially as local manufacturing sprung up in England, France and Germany, and many large European countries. The price of a pair of spectacles in England during the late 1400s was about 8-18 schillings, at a time when a middle-class stonemason was earning about 17 shillings per day.* Spectacles were becoming attainable by the middle class.
They say all fashion trends come back around, but the early Rivet eyeglasses from the 1280-1400 era are unlikely to mount a come-back any time soon. But 220 + years is a pretty good run for one style! However, they were fairly unattractive counting as the Birth Control Glasses of their day. Since the earliest customers were scholarly monks, this didn’t matter, but as demand drifted into other professions, at some point they would need to become more stylish.
Summary: Venice’s switch to glass for lenses in 1301 from quartz, the taxation of spectacles in 1321, and spectacles reaching England by 1326 are huge indicators that the new eyeglass industry was profitable and growing rapidly. This is surprising for an era where travel and communication were extremely difficult and most technological advances were very slow. After all, it took hundreds of years for men to move from wearing robes to pants. Judges and Catholic priests still haven’t made the jump to this very day, at least at work, as examples of the Roman preference for robes extending for millennia.
Venice at this time was an enormously rich and influential city-state at the center of trade routes that reached England, Russia, Byzantine Empire, India, and even China. There was no better city to in which start a trend. Once spectacles took hold in Venice around 1300 their use spread, even reaching faraway England by at least 1326, a rapid technological jump for that era.
The development of Spectacles was made possible by the advances in glassmaking borrowed from the stained glass used in Gothic Cathedrals. Improved printing and the increasing availability of books fueled the demand for better reading vision. Both of these technologies worked together increased demand for spectacles and sparked their continued improvements.
Please buy Neil Handley’s must have book: Cult Eyewear
Credit where Credit is Due:
I’d especially like to thank the world’s most knowledgeable Ophthalmic Optics Historian, Neil Handley MA, Museum Curator, College of Optometrists, London UK, for allowing the use of his many unpublished historical gems. Neil has greatly advanced our historical knowledge of this era especially in regard to England.
Handley, Neil (2011). Cult Eyewear. Merrell Publishers
Ayliffe, Will (2011). The Correction of Optical Defects from Spectacle to Laser (Power Point Slides in PDF) Presentation in my personal collection. (Professor Ayliffe PhD teaches at Gresham College, UK.)
The combined contributions of Mr. Handley research used in Professor Ayliff PPT are noted in the text with an asterisk (*).
Rosenthal, J. William, et al (1996). Spectacles and Other Vision Aids: A History and Guide to Collecting. Norman Publishing. (Dr. Rosenthal is a noted historian and collector of eyewear)
Bruneni, Joseph L. (1994) An Illustrated History of the American Opthalmic Industry, Optical Laboratories Assocation. (Joseph L Bruneni was an Optician who taught Opthalmic Optics at the Southern California College of Optometry)
Shreiner, E.E. (1919) Colored Glass, Including a History of Glass and Glass Terms. McCoy and Stillwell Opticians
Wikipedia, of course. Who knew they would have so many gems?