She isn't a super-thin beauty that the fashion magazine she works for glamorizes. To her co-workers, she is an ordinary, slightly plump girl known as Betty Suarez — "Ugly Betty" that is. And although she is highly intelligent, sweet and very hardworking, on first glance, you would more likely notice her prim and proper outfits, braces and thick, red-framed glasses.

Since image is everything, are those glasses Ugly Betty's way of trying to make a fashion statement in the world of high fashion? In her case, it's more likely to correct her vision. But how do the extra two eyes of a "four-eyes" work? How do the lenses in glasses or contacts help us see better? And who on earth came up with them anyway?

In Italy in the late 1200's, people wearing glasses started showing up in Italian paintings. At first, only rich or well-educated people like professors or priests wore them, but after the 1500's, when books became widely available, glasses became more popular among the common people. Fast Fact: In a normal life-span, your eyes will bring you almost 24 million images of the world around you.

Although glasses spread quickly throughout Europe and Asia, the biggest problem was keeping them on. It took nearly four hundred years before opticians came up with a brilliant invention: sidepieces for the nose!

The eye works like a camera to collect light from an image through the pupil and focus it onto the retina, a layered area of cells at the back of the eye that works as the 'film.' The pattern of light is then conveyed as electrical signals via the optic nerve to the brain. The brain, in turn, translates this back into an image. Fast Fact: Our eyes can process 36,000 bits of information every hour.

The cornea, the transparent covering at the front of the eye, and a lens inside the eye work together to converge the light (bring it together) precisely on the retina for a sharp, clear image. When you look at something, small muscles automatically change the shape of the lens and keep the object on the retina, even when your eyes move.

In some people though, like Betty Suarez, the eyes fail to focus the image on the retina in the right spot and it is focused either in front or behind the retina.

If you are affected by myopia, or nearsightedness, your lens elements converge the light too early and the image is focused in front of the retina. Near objects are focused closer to the retina and are seen best but people with myopia have troubles seeing images far away.

Fast Fact: The adult eyeball measures about 2.5 cm (1 inch) in diameter. Of its total surface area only one-sixth is exposed -- the front portion.

Another type of disorder is hyperopia, or farsightedness, where light is focused behind the retina (or would if it didn't reach the retina first). In this case, far objects are seen best and there is difficulty seeing things up close since the eye doesn't converge the light enough.

Glasses or contact lenses (which are worn directly on the cornea of the eye) work by "correcting refractive errors". In other words, they do some of the work of bending the light to help out your lens and cornea, and you can then see clearly.

The right shape and power of lens in front of the eye will adjust where the image is focused so it will be on the retina. Light passing through a corrective lens is always bent away toward the thickest part. Strength is determined by the lens material and the angle of the curve.

A 'minus lens', is concave and thickest on the sides. Myopia, in which your eye is too strong, can be corrected by using a concave lens to diverge, or spread out, the light so that when it passes through the real lens system, it comes to focus further back than it normally would - on the retina where it belongs. In a 'plus lens', which is convex, the thickest part is the middle and the thinnest part, the edges. Light rays bend toward the middle. A convex lens corrects hyperopia, in which your eye is too weak, by converging the light so that when it passes through the real lens system, it focuses further forward than it normally would. Fast Fact: The lens power of eyeglasses is measured in units called diopters.

In astigmatism, there is a distortion in the shape of the cornea, resulting in two focal points and blurring of images. A lens that corrects for this can be combined with one of the other lenses to also correct for nearsightedness or farsightedness.

Some older people develop presbyopia, in which the cornea and lens become less stretchy and can't change shape as well. They have trouble focusing light from both near and far objects and have to wear bifocals, with the top for seeing far objects and the bottom for near ones. Lenses can even be made to move the image for one eye, correcting double vision when the eyes don't move together ('crossed eyes').

And that's how glasses work. I hope that's "clear!" And who did invent glasses anyway? Well, like Betty's sense of style to some, to this day, that remains a mystery.

Learn More!

ABC.com: Ugly Betty

All About Vision for Teens

Optics

Optics and Vision Tests

Dr. Hasini Reddy is a Rhodes Scholar whose PhD research focused on brain imaging techniques (University of Oxford, England). She completed her medical degree at Memorial University (St. John’s, ND), and is now a medical resident at the University of Western Ontario specializing in neurology and pathology. She enjoys reading, traveling and horseback riding.

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