Glasses have come a long way since their creation in the early days of human civilization. They have now become an everyday accessory for those struggling with vision problems. But how do glasses work? Continue reading to learn more about eyeglasses with the eye care professionals at Nationwide Vision.

Refractive errors can be corrected with the help of refraction, as we can manipulate the speed and direction of the light passing through the glass. This allows us to focus the light on the correct portion of our retina.

There are different types of refractive errors that have varying prescription lens shapes. Continue reading to learn more about each of the four refractive errors.

The Four Types of Refractive Errors

Myopia

Myopia can cause distant objects to appear blurry. This condition is caused by a variety of factors, such as an eyeball that’s too long. Myopia can also be called nearsightedness.

Hyperopia

Individuals with hyperopia will have trouble seeing up close objects. It can also be called farsightedness and is caused by the reflection of an image that’s focused behind the retina.

Astigmatism

An unevenly shaped cornea can lead to the eye having more than one focal point. This can cause vision blurry for both near and far distances.

Presbyopia

This refractive error is caused by the eye’s natural aging process. As you age, the natural lens in your eye becomes less effective at focusing the light on your retina. This can make seeing near objects quite difficult.

How Glasses Have Evolved Over the Years

The Reading Stone

Abbas ibn Firnas is believed to have discovered and created the first reading stone in the 9th century. The reading glass was a small piece of glass that magnified text, making it easier to read small print.

This invention led to the discovery of reshaping light to aid with vision problems. As the science behind the reading stone advanced, so did our ability to correct common vision problems.

The Creation of Renaissance Era Eye Wear

The earliest type of eyeglass lenses were created in the 13th century by glassblowers. It was found that shaping the form of the glass can change the way the light passes through it. The glassblowers then realized that changing the direction of the light could aid those experiencing problems with their vision and help them see clearly. 

The first group of people to use these were monks, who wore them on their nose or held them like a magnifying glass. 

Eyeglass frames similar the ones we know today weren’t created until the Renaissance era. These frames were fashioned with arms that fit behind the ears and made from readily available materials such as animal bone or wood.

What Eyeglasses Can Treat Today

Glasses today come in a variety of forms and can treat many different types of vision problems. The eyeglass shape can be modified to correct refractive errors or other vision problems.  

Convex lenses are lenses that are thicker in the middle and thinner on the ends. These lenses can help magnify images to correct farsightedness. 

Concave lenses are lenses that are made to be thicker at the edges and thinner in the middle. Concave lenses can correct nearsightedness.

We also have prescription eyeglasses that treat presbyopia thanks to Benjamin Franklin’s discovery in 1784. There are now many more options available for those who have presbyopia, such as bifocal or trifocal lenses. 

Cylindrical lenses, which have an asymmetrical thickness, are prescribed for astigmatism.