Eyeglasses

By Rick Sapp

The eye is the primary means—though not the only means because humans also hear, smell, taste, feel, and perhaps sense a hidden sixth dimension—with which we interpret our surroundings. Often, however, the eye does not work as it should. Eyeglasses are the answer. The first true eyeglasses were made in Italy in about 1286 and have been constantly refined and improved since then. It is commonly accepted that the American printer, inventor, statesman, and man-about-town Benjamin Franklin of Philadelphia invented bifocals—a life-saver for older eyeglass wearers—and several paintings of him portray him wearing glasses. Although the basic eyeglass design has changed little since Benjamin Franklin’s time, the materials and processes used to fashion today’s eyeglasses have improved dramatically. Not only do modern eyeglasses improve the wearer’s vision, they also protect the wearer’s eyes from sun damage. Eyeglass frames and lens colors are considered by many to be fashion statements of the utmost importance. Elton John is an excellent example of this belief. The eyeglass frames highlighted in this book are only a very small sampling of the entire universe of designs available today to the eyeglass wearer.

• Language: English
• Publisher: TAJ Books International
• Release date: Mar 3, 2013
• ISBN: 9781844062829

Rick Sapp

Born near Chicago, Rick Sapp grew up on Amelia Island, Florida. His unusual heritage— on one side a long line of southern farmers, shrimp boat captains and rebels, and on the other, a legacy of northern coal miners, gangsters and union organizers—gave him a restless spirit and an inquisitive mind. After three years at the U.S. Air Force Academy he joined the army as a paratrooper and subsequently worked as an intelligence officer in Europe. He completed his PhD. in cultural anthropology at the University of Florida, conducting field work with the National Institute of Mental Health (St. Elizabeth Hospital) in Washington, DC, and in the Great Bend of the Suwannee River, Florida. Rick owned a Media Consulting firm until 9/11 and soon thereafter began freelancing full-time. Rick has since authored (or coauthored) 30 books about camping, bicycle touring, urban redevelopment, history, political cartoons, and outdoor activities. A prolific freelance writer since 1980, his resume includes hundreds, perhaps a thousand, nonfiction articles, creative nonfiction, and short fiction stories, and even poetry. Rick lives in Florida.

Book preview

EYEGLASSES

Acomplex biological instrument, the eye is the primary means—though not the only means because humans also hear, smell, taste, feel, and perhaps sense a hidden sixth dimension—with which we interpret our surroundings. The eyeball collects light from the environment, either directly from a source, such as the sun or a light bulb, or indirectly such as a reflection. It regulates light intensity through its diaphragm, then focuses it through an automatically adjustable (when all parts are working properly) assembly of lenses to form an image on the retina. Then it converts this image into a set of electrical signals and transmits the signals to the brain through complex neural pathways (the optic nerve) to the visual cortex and other areas of the brain.

The eye converts light into electro-chemical impulses in neurons, electrically excitable cells that process and transmit information by electrical and chemical signaling. Apparently all organisms see only a small range of the full electromagnetic spectrum. This varies from creature to creature, but is mainly between wavelengths of 400 and 700 nanometers. Scientists hypothesize that this is probably due to the underwater evolution of the eye: water blocks out all but two small windows of the spectrum, and there has been no evolutionary pressure among land animals to broaden this range. Without further evolutionary pressure, humans may never know what wonderful colors lie above our short visible spectrum: colors with faster wave lengths in the UltraViolet, X-ray, and gamma-ray fields. The same can be said for those wave lengths of light that are much longer than our peep hole at the universe: the infrared, microwave, radio, television, and mysterious long waves.

The process of seeing and understanding the world is subject not only to errors in mental interpretation, but to physical and chemical difficulties in the eyes and the neural pathways themselves. Genetics rears its head and not every eye is formed perfectly at birth. By the end of an individual’s life, especially if it is a long life, many things will have happened—accidents, disease, the natural process of aging—that alter and stress the eyeball. The eye is a fragile instrument. The eye globe is filled with nothing more substantial than a jelly-like material called vitreous humor.

We call the most common difficulties in perception myopia (nearsighted), hyperopia (farsighted), and astigmatism. When light is not properly focused on our retina, refractive errors occur. Myopia prevents individuals from seeing clearly at a distance because the image focuses in front of the retina due to the eyeball being compressed or lengthened. Close work or reading is not affected. Hyperopia prevents individuals from seeing well at close tasks because the image focuses behind the retina due to the eyeball being compressed. When the lens of the eye loses its ability to focus, often becoming hardened or crystalline with age and thus causing difficulties seeing objects up close, it is called presbyopia. Individuals with astigmatism experience blurred vision because the cornea of the eye is irregularly shaped.

French Empire gilt scissors glasses, c. 1805

One in ten men is color blind to some extent, most commonly in the complementary red and green sectors of the spectrum. Curiously, this evidently hereditary sight defect is rare in carriers of XX chromosomes, or women. Defective color sensitivity is usually a fault of the cone cells in the retina because the rod cells are black-and-white receptors. The most severe form of color blindness is called achromatopsia. A person with this rare condition cannot see any color; they