The History of Corrective Lenses

Nearsightedness and farsightedness, also known as myopia and hyperopia, are both common conditions that have affected humanity since ancient times. Unlike many chronic conditions that require surgery or precise medications to treat, these refractive errors can be corrected with lenses that magnify images properly through the eyes. Because of this, we can find evidence of corrective lens usage dating back much further than many modern medical treatments. 

Polished magnifying lenses have been unearthed dating back as far as 1600 BCE. The function of ancient lenses has been highly debated, with most historians agreeing that they were likely used as burning-glasses to focus the sun’s rays and start fires, or as magnifiers to study the stars more closely. Some of the lenses are of sufficient quality that they could have been used as magnifying glasses, but even by the 1st century CE, this didn’t seem to be common knowledge. Seneca the Younger, a Roman writer, remarked upon the magnifying effect of a glass globe filled with water, but may have mistakenly attributed the property of magnification to the water instead of the glass. Despite the abundance of ancient lenses, few historians believe they were used to correct vision.

During the Islamic Golden Age, characterized by rapid advancements in medicine, math, and astronomy, the Arab mathematician Ibn al-Haytham wrote Kitāb al-Manāẓir, or the Book of Optics. In 1021, he was the first to describe the magnifying property of curved glass surfaces, and he even demonstrated his work by making reading globes. This knowledge did not reach the West until the end of the 12th century, when it was translated from Arabic into Latin in Italy. Not only did Ibn Al-Haytham provide a physical explanation for the phenomenon of magnification, but he also provided a revolutionary practical insight. Reading stones, polished into convex hemispheres, soon became the first widely used vision aids.

The only known illustration of reading stones is placed on the book on the bottom right. Madonna and Child with St. Anne and St. Ursula with Holy Virgins (detail), by Ludwig Konraiter, c. 1485.

By the 13th century, Italian artisans had combined two convex lenses into a wearable frame to correct vision, the first true eyeglasses. Even though those familiar with Ibn Al-Haytham’s work would have known that glass made the best lenses, these early glasses were made of various clear rock crystals because it was difficult to make colorless glass. In the next century, however, the discovery of colorless glass paste made lenses much more affordable, and they began to be produced at a significant scale. 

Now that eyeglasses were properly developed, the journey of discovery toward precise vision correction could begin. Over the centuries, lenses became more refined. The bifocal lenses were invented in 1784, allowing correction of vision at both near and far distances simultaneously. Around the same time, custom lenses were designed to correct astigmatism. As lenses became more precise, eye doctors could begin providing precise corrections for individuals. But how could they identify the correct prescription? 

In the 1860s, Hermann Snellen developed his Snellen eye chart, a visual acuity test that has the appearance most people recognize today. A doctor can measure a patient’s subjective refractive error by having them read off the letters of the Snellen chart from 20 feet away. Snellen designed the chart to represent normal visual acuity at 20/20. The numerator represents the distance, in feet, from the chart at which the patient is standing, and the denominator is the distance at which a person with perfect eyesight can still read the smallest line the patient can clearly visualize. 20/40 vision, for example, would be a patient standing 20 feet away who can clearly read until the line that a person with normal visual acuity could read from 40 feet away.

Various Snellen eye charts, including the Tumbling E, are used to test visual acuity for people who cannot read. The patient would point in the direction each E was facing rather than reading the letters.

While many today may still recall using the Snellen eye chart in the doctor’s office, most subjective vision acuity tests are now performed with the phoropter, invented in the early 1900s. This is the machine used when the doctor works through various corrective options, asking the patient, “Which is clearer? Option 1 or 2?” until they can discern the patient’s prescription. An even more modern invention is the autorefractor, developed in the 1970s. This computer-controlled machine often features the famous hot air balloon image and provides an objective measurement of a person’s visual acuity. Despite the valuable information an autorefractor provides, it is used only as the starting point for further subjective refraction tests.

Modern prescription lenses, along with other corrective options such as contact lenses, may become even more vital in the coming years. Myopia, or nearsightedness, has reached epidemic levels worldwide, and it has been estimated that by 2050, half of the world’s population will be nearsighted. Studies have affirmed that increasing amounts of time spent inside increases the risk of developing myopia. Interestingly, the differing “visual diet” of light wavelengths between outdoor and indoor exposures may be environmental factors that affect the development of myopia, although more research is needed. No matter the exact cause, it is well-researched that spending more time outdoors appears to protect against myopia. 

Given the rapid increase in myopia, there have been calls in the U.S. to classify myopia as a disease. This status would help underscore its health consequences and attract attention and funding dollars for effective screening, treatment, prevention, and research. Our understanding of refractive errors continues to evolve as the world changes and new problems arise. As modern vision researchers seek to understand the development of myopia and other conditions, they can be assured that they continue a legacy of innovation dating back more than 1,000 years.

Thank you for reading,

Ashby Glover

Sources

Atlantic Eye Institute. “History of the Eye Chart.” Accessed March 15, 2026. https://atlanticeyeinstitute.com/history-of-the-eye-chart/

Bharat Gurnani and Kirandeep Kaur. “Autorefractors.” StatPearls (Internet). Treasure Island (FL): StatPearls Publishing, Jun 11, 2023. https://www.ncbi.nlm.nih.gov/books/NBK580520/ 

Daniel Azzam and Yasmyne Ronquillo. “Snellen Chart.” StatPearls (Internet). Treasure Island (FL): StatPearls Publishing, May 1, 2023. https://www.ncbi.nlm.nih.gov/books/NBK558961/

Gary Stix. “The Nearsightedness Epidemic Has Become a Global Health Issue.” Scientific American, October 1, 2024. https://www.scientificamerican.com/article/nearsightedness-has-become-a-global-health-issue

Glasses.com. “When Were Glasses Invented? A Complete, EvidenceBased History.” February 17, 2026. https://www.glasses.com/gl-us/blog/when-were-glasses-invented 

Jerry Norman. “A Venetian Ordinance on the Production of Lenses Suggests that they Were Extensively Used for Reading by This Date: 4/2/1300.” Jerry Norman’s HistoryofInformation.com. https://www.historyofinformation.com/detail.php?id=2217 

New England College of Optometry. “The Phoropter: Optometry Equipment or Dinosaur?” Accessed March 15, 2026. https://www.neco.edu/the-phoropter/ 

Sean O’Hare. “Ancient Optical Lenses.” Ancient Cinema, Accessed March 15, 2026. https://www.ancient-cinema.org/index.php/stories/77-ancient-optical-lenses

State University of New York: College of Optometry. “New Research Suggests Myopia Could Be Caused By How We Use Our Eyes Indoors.” February 17, 2026. https://www.sunyopt.edu/new-research-suggests-myopia-could-be-caused-by-how-we-use-our-eyes-indoors/

Stefana Sabin. “The Gradual Discovery of Glasses: Considering the prehistory of spectacles.” Laphams’s Quarterly, September 29, 2021. https://www.laphamsquarterly.org/roundtable/gradual-discovery-glasses