# Eyeglasses

> Lenses that extend a working life

- Date: c. 1286
- Era: Middle Ages
- Domain: [Optics & Imaging](https://lastcodex.org/en/domains/optics/)
- Rebuild stage: III (Crafts & cities)
- Difficulty: 3/5
- URL: https://lastcodex.org/en/inventions/eyeglasses/

Eyeglasses are a pair of lenses held in a frame in front of the eyes to correct long sight, short sight or astigmatism. They appeared in Italy in the 1280s as reading aids for older people; lenses for short sight followed in the fifteenth century and side arms in the eighteenth.

![Eyeglasses · Lenses that extend a working life](https://lastcodex.org/_astro/plate.p-YqvYdA_Z9TWE6.webp)

## Legend

1. Biconvex glass lens
2. Bone rim
3. Handle
4. Iron rivet
5. Copper wire binding

## What it is

Eyeglasses, or spectacles, put a lens in front of each eye so that the light reaches the retina already bent by the right amount. The first ones helped people in their forties and older to read and to do fine work, once focusing at reading distance had become hard.

The pair on the plate is the oldest type, the rivet spectacles of the fourteenth and fifteenth centuries. Each glass lens sits in a ring carved from bone, wood or horn. A short handle sticks out from each ring, and the two handles are joined by a single rivet. The pair has no side arms: the rivet rests on the bridge of the nose and the rims pinch the nose on either side, so the wearer has to keep the head level or hold the spectacles with one hand.

## How it works

![A clear dome of rock crystal resting on a dried leaf, enlarging the veins beneath it](https://lastcodex.org/_astro/v1.6SkuV2SN_Z1hO8WQ.webp)
_A reading stone, a dome of crystal or glass laid on the page, was the magnifier that came before spectacles._

Inside the eye, a soft lens changes shape to bring near or distant things into focus. With age it hardens, and the closest point the eye can see sharply moves away: a few centimetres from a child's face, it ends up out of reach of the arms for most people of sixty. This is presbyopia, and it is why reading glasses were the first ones made.

A convex lens, thicker in the middle than at the edge, makes the light converge a little before it enters the eye, and so does part of the work that the eye's own lens can no longer do. Opticians measure this power in dioptres, the inverse of the focal length in metres. A reading lens of +2 dioptres brings parallel light to a point 50 cm behind it.

Short sight is a different focusing problem, and it can come on top of presbyopia. The eyeball is a little too long, or its optics too strong, and distant things blur. A concave lens, thinner in the middle, spreads the light slightly before it enters the eye and pushes the image back onto the retina. Lenses of this kind were being ground in Florence in the fifteenth century. In astigmatism the eye's power differs between two perpendicular directions, so lines at one angle blur more than lines at another. Correcting it needs a lens curved more in one direction than the other, and such lenses came much later.

## How to build it

A pair of rivet spectacles like the one on the plate takes two lenses, a piece of bone or hardwood, copper wire and one small rivet.

![A bronze grinding tool on a wooden block, a glass blank fixed with pitch to a wooden handle, a pot of abrasive and a piece of leather](https://lastcodex.org/_astro/v2.BqgmtbS7_4limR.webp)
_The glass blank, fixed with pitch to a wooden handle, was worked with wet abrasive in a bronze tool, then polished on leather._

**Get the lenses.** For a pair you will actually look through, take two lenses from a cheap pair of modern reading glasses. Grinding your own is a historical demonstration: as a spectacle maker did, rub a disc of glass about 4 cm across with wet abrasive powder inside a tool hollowed to the curve you want, finishing with finer and finer grits, then polish it with rouge on leather or felt. For a +2 dioptre lens made of ordinary glass, both faces need a radius of curvature of about 50 cm, a very shallow curve. Hand-ground lenses will not have an exact power, and their optical centres will not be lined up with your pupils.

**Cut the rims.** Mark two circles on a flat piece of bone or boxwood with dividers, a little larger than the lenses, and saw them out with a fine saw, leaving a short tab on each ring for the handle. Cut a V-shaped groove around the inside of each rim to hold the edge of the lens.

**Split and bind.** Saw through each rim on the side opposite the handle. Spring the ring open, slide the lens into the groove and close the split by wrapping thin copper wire several times around two small lobes left on either side of it.

**Rivet the handles.** Drill a small hole near the end of each handle, overlap them and set a copper or iron rivet, peened just tight enough that the two halves can still be folded. File small notches along the inner edges where the rims meet the nose, so they grip better.

> **Safety.** Grind glass wet and wear a dust mask: dry glass and abrasive dust harm the lungs. Wear eye protection when drilling bone and cutting wire, and handle cut glass with care. Never look at the Sun through a lens, and never leave one in sunlight near paper or wood, because it can start a fire. This pair is a replica: do not use it in place of glasses prescribed and fitted by an optometrist, and never drive with it.

## History and evolution

Polished crystals and glass had been used to enlarge writing long before spectacles. The step of setting a lens in a frame in front of each eye came in Italy around 1280 to 1290. Where exactly is not known: Pisa and Florence are often proposed, and a Venetian ordinance of 1300 already punished glassmakers who sold glass "discs for the eyes" as rock crystal. In a sermon given in Florence in 1306, the Dominican friar Giordano da Pisa said that the art of making spectacles was not yet twenty years old and that he had spoken with the man who first made them. Nobody knows his name.

The oldest known painting of spectacles is a fresco of 1352 by Tommaso da Modena in the chapter house of San Nicolò in Treviso, which shows a Dominican cardinal reading with rivet spectacles. Real frames rarely survive. A bone pair from the fifteenth century was found at Trig Lane, by the Thames in London, at a time when thousands of spectacles a year were imported into London from the Low Countries. In 1466 the Duke of Milan ordered two hundred pairs graded by age, a sign that lens strengths had become fairly standard.

![Late eighteenth-century steel spectacles with side arms ending in rings, each lens divided in two halves along a horizontal line](https://lastcodex.org/_astro/v3.DUb3gJmE_Z25HHcK.webp)
_Double spectacles of the late eighteenth century: a distance lens above, a reading lens below._

By the early sixteenth century spectacles could correct short sight as well as long sight, and bridges of leather or whalebone replaced the rivet. Around 1730 the London optician Edward Scarlett is credited with adding rigid side arms, or temples, that pressed against the sides of the head. In letters of 1784 and 1785 Benjamin Franklin described his "double spectacles", with half of each lens for distance and half for reading. Pince-nez, held by a spring on the nose, followed in the nineteenth century, then in the twentieth plastic frames, lighter plastic lenses and, later, thinner high-index lenses.

## Key figures

- Early Venetian record: Ordinance of 2 April 1300 on glass "discs for the eyes"
- Testimony on the date: Sermon by Giordano da Pisa, Florence, 1306: the art was "not yet twenty years" old
- First painted spectacles: 1352, fresco by Tommaso da Modena in Treviso
- A typical reading lens: +2 dioptres, a focal length of 50 cm
- Side arms (temples): Credited to the London optician Edward Scarlett, about 1730

## Requires

- [Glass](https://lastcodex.org/en/inventions/glass/): Melted sand you can see through (c. 2,500 BCE)

## Leads to

- [Microscope](https://lastcodex.org/en/inventions/microscope/): A world too small to see (c. 1590)
- [Telescope](https://lastcodex.org/en/inventions/telescope/): Bringing the distant close (1608)

## Sources

- [History of spectacles](https://www.college-optometrists.org/history-of-spectacles), College of Optometrists, British Optical Association Museum
- [Spectacles (bone rivet spectacles from Trig Lane)](https://www.londonmuseum.org.uk/collections/v/object-407684/spectacles/), London Museum
- [Medieval Eyeglasses: Wearable Technology of the Thirteenth Century](https://www.medievalists.net/2016/03/medieval-eyeglasses-wearable-technology-of-the-thirteenth-century/), Medievalists.net
- [The Earliest Depiction of Eyeglasses in a Painted Work of Art](https://www.historyofinformation.com/detail.php?id=1447), HistoryofInformation.com
- [A Venetian ordinance on the production of lenses (2 April 1300)](https://historyofinformation.com/detail.php?id=2217), HistoryofInformation.com
- [Renaissance Vision from Spectacles to Telescopes (Vincent Ilardi, 2007), book description](https://www.goodreads.com/book/show/1685277.Renaissance_Vision_from_Spectacles_to_Telescopes), American Philosophical Society, via Goodreads
- [Benjamin Franklin invents bifocal glasses](https://www.history.com/this-day-in-history/may-23/benjamin-franklin-invents-bifocal-glasses), HISTORY.com
- [University Physics Volume 3, 2.5 The Eye](https://openstax.org/books/university-physics-volume-3/pages/2-5-the-eye), OpenStax, Rice University
- [Presbyopia](https://eyewiki.org/Presbyopia), EyeWiki, American Academy of Ophthalmology
- [A Review of Depth of Focus in Measurement of the Amplitude of Accommodation (Burns, Allen, Edgar and Evans, Vision 2, 2018)](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6835437/), MDPI, via PubMed Central
- [Optics of the Human Eye (Atchison and Smith, 2nd edition, 2023)](https://www.routledge.com/Optics-of-the-Human-Eye/Atchison/p/book/9781003128601), CRC Press
- [Schematic eyes: Gullstrand, Gullstrand-Emsley and reduced eyes (lecture notes)](https://www.uomus.edu.iq/img/lectures21/MUCLecture_2024_11210775.pdf), Al-Mustaqbal University

Fact-checked on 2026-10-12.

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The Last Codex · https://lastcodex.org/en/inventions/eyeglasses/ · © The Last Codex. Texts, plates and figures: CC BY-NC-ND 4.0.