Sight for Sore Eyes: The Invention of Eyeglasses
- Ray & Gale Lawson Home School Enrichment
- 2010 14 Jun
Want evidence that God is the Almighty Creator? Look no further than your eyes! The eye is an incredibly complex organ that has never been duplicated by science, no matter how hard man tries.
Although the eye is an incredible piece of God's work, some of us (the authors of this article included) need a little help to take full advantage of our sense of sight. We have to wear glasses. Glasses are optical devices that compensate for problems with our eyes—that is, they help us see more clearly.
If you wear glasses and you take them off, how does that affect what you see? Can you imagine if eyeglasses had never been invented? For many of us, the world would be a much different place. Eyeglasses are an invention that has changed the world!
The World Before Eyeglasses
Our story begins in the book of Jonah, Chapter 1:1-2: "Now the word of the Lord came unto Jonah the son of Amittai, saying, Arise, go to Nineveh, that great city, and cry against it; for their wickedness is come up before me."
Around the year 1845, a British archaeologist named Austen Henry Layard was excavating the ruins in Kuyunjik, Iraq. The ruined city he was excavating was formerly known as Nineveh, the ancient capital of Assyria. Layard found an interesting object in the ruins: a ground crystal oval you could see through. He did not know exactly what it was or what it was intended for.
Layard presented the strange object to a friend, Sir David Brewster, a Scottish physicist who was also a licensed preacher. Brewster's scientific work revolved around the study of optics. Although Brewster could not be sure, this crystal oval seemed to be a magnifying glass that may have been used for reading. In 1853 he presented it to the British Association for the Advancement of Science, showing the association its magnifying capability. This may have been the first optical device used to help people see more clearly.
The Roman statesman Seneca supposedly used a glass sphere, filled with water, to act as a magnifier so he could read all of the books of Rome. The combination of the spherical shape and the water inside formed a simple optical lens.
By medieval times, optical devices called "reading stones" were fairly common. These stones were lenses that, when placed on top of a written document, magnified the letters to help a person read.
Brewster noted that the Assyrian crystal had a "bi-convex" shape, meaning it was curved outward on both sides. His recognition of this particular shape eventually led to the development of the Coddington magnifier. Brewster, along with fellow physicist William Hyde Wollaston, used the design from the Nineveh lens to make the Coddington magnifier.
While the art and science of glassmaking can be traced back to the late Bronze Age (1550-1200 BC), the earliest glass was used for vessels and ornaments. It was not of the optical quality required for making lenses. God, however, had already made glass! Certain crystal materials, such as emerald and quartz, already existed. These crystal materials were perfectly formed and only needed to be shaped to create visual magnification. It is believed that the emperor Nero used a piece of emerald to correct his vision when he was watching gladiators.
Although the magnifying lens from Nineveh may well have been the first lens, scientists in the 1200s knew about lenses and how they could be used to magnify objects to help correct a person's vision. It was during that century that the first wearable eyeglasses began to emerge.
The Invention of Eyeglasses
Who invented the world's first wearable eyeglasses? The truth is no one really knows for sure. An Italian named Salvino D'Armate is often credited with the invention. His tomb, which no longer exists, was said to have the inscription: Here lies Salvino degl' Armati, son of Armato of Florence, inventor of eyeglasses. May God forgive his sins. AD 1317.
A Dominican friar named Alessandro Spina, also from Italy, is also given credit, but it is thought that he made glasses after watching someone else make them first. In any case, eyeglasses similar to those we are familiar with today were in use by the late 1200s.
Although glasses were then being manufactured and used to correct vision, it was not until 1604 that Johannes Kepler (a Christian who was profiled in Home School Enrichment in the May/June 2003 issue) published his work on how and why convex and concave lenses worked. Now the apparent mystery was gone, and inventors began to rapidly improve the design of glasses.
The first eyeglasses were lenses mounted in frames that had to be worn on the bridge of one's nose. Wearing glasses turned out to be somewhat of a balancing act! In the 17th century, Spanish spectacle makers used strips of silk ribbon that could be attached to the glasses and looped over the wearer's ears to help keep them on. In 1752, an inventor named James Ayscough began to sell glasses that had hinged metal side pieces. These side pieces allowed a person to open the eyeglasses and place them on. The side pieces hooked over the ears and kept them secure. They soon after became extremely popular.
Another improvement, which many of us are thankful for today, came from Benjamin Franklin. Franklin suffered from two vision conditions. The first, called myopia, or nearsightedness, makes it more difficult to see far away. The second problem he suffered from was presbyopia, which is the inability of the eye to focus as one gets older. Franklin found that, depending on what he was doing, he needed two pairs of glasses handy. To solve this problem, he invented bifocals. Each lens of Franklin's bifocals was actually made of two lenses with different convex characteristics. One lens allowed him to see faraway objects, while the second allowed him to focus.
The World After Eyeglasses
As techniques and methods for manufacturing optical glasses and plastics improved, a number of innovations followed. Bifocals are now made by molding two lenses together instead of "cementing" two lenses as in Benjamin Franklin's time. For some people, bifocals do not quite help enough, so inventors came up with trifocal glasses. As you might expect, these glasses have three lenses together.
Bifocals and trifocals can sometimes cause problems for the person wearing them. As the eye shifts between the lenses, the change in magnification can cause the wearer to feel eye fatigue and stress leading to headaches. To help with this problem, optical inventors developed yet another approach: progressive lenses.
Progressive lenses, which were originally called "Varilux" lenses, have smooth lenses instead of the lines between different sections that make up bifocals and trifocals. Smooth lenses make it easier for a person to change the magnification with only very slight movement of the eyes and head. This eliminates a lot of the fatigue and stress that causes headaches. Progressive lenses are not perfect either. These lenses have some optical characteristics that can cause the image to be slightly out of focus. They are more complicated and costly to make than the simpler forms, and they require much more accurate design to match the needs of the user's eyes.
Another type of lens used to correct vision is called the contact lens. In 1508, the famed inventor Leonardo da Vinci came up with the idea for contact lenses, but it would be over 300 years before someone actually made the first "hard" contact lens. It was not until 1961 that a Czech inventor named Otto Wichterle, a chemist, would develop the specialized materials and processes to manufacture optical gels, leading to today's "soft" contact lenses.
As with so many inventions, sometimes it takes one invention to lead to another. One example is the laser. A laser is an accurate, precise light source that scientists and researchers have been able to use in many different fields. One such field is eye surgery. In 1950, in Bogota, Columbia, a Spanish ophthalmologist named Jose Barraquer used a laser to perform corrective surgery on a patient's cornea. The result was that the patient's vision was improved without glasses! Medical researchers continued developing the process, and today it is commonly known as Lasik surgery.
Many kinds of specialized glasses have been developed. Sunglasses, which were originally called "sun cheaters," use special materials to filter out harmful infrared and ultraviolet rays from the sun. These are a form of protective glasses. Safety glasses are glasses made from shatterproof plastic. Many have "side shields" of shatterproof plastic that wrap around the sides of the head. (As a side note, safety glasses are highly recommended if you are doing any work that can cause chips of wood, metal, or other materials to fly toward your face. They are inexpensive but very important for protecting your sight.)
Focus on Some Optical Words
- Concave - hollowed, or rounded inward, like a bowl.
- Convex - curved, or rounded outward, like the outside of a sphere.
- Ophthalmologist - a physician who deals with the structure, function, and diseases of the eye.
- Optician - a maker of optical equipment and glasses.
- Optometrist - a specialist licensed to examine the eye for defects and faults of refraction, who can prescribe lenses and eye exercises, diagnose diseases of the eye, and refer patients for treatment.
- Polarization - the action of controlling light rays to assume a definite form. Sunglasses use polarized glass to cause the harmful rays of the sun to reflect away from your eyes.
- Refraction - the deflection of a ray of light as it passes through one medium (such as air) into a different medium (such as a glass lens).
*This article first published on June 16, 2010
Ray and Gale Lawson have been homeschooling their three children since 1995. Ray holds a BS in Electrical Engineering from the Virginia Military Institute and is also a student, pursuing a Masters in Nuclear Engineering at the University of South Carolina. He works for Savannah River Nuclear Solutions, LLC. Gale holds a BS in Mechanical Engineering from the University of South Carolina and is full-time mom and teacher. They are members of Breezy Hill Baptist Church in Graniteville, SC. Questions, comments and suggestions are always welcomed and can be e-mailed to them at firstname.lastname@example.org (Ray) or email@example.com (Gale).
This article was originally published in the Mar/Apr 2010 issue of Home School Enrichment Magazine. Sign up now to receive a FREE sample copy! Visit www.HSEmagazine.com today!