![]() This era also ushered in the pince-nez spectacles, which had no ear pieces but instead stayed in place via a nose clip the scissors spectacles, which folded on a hinge for quick storage in a shirt pocket or vest and cylindrical lenses, which curve asymmetrically to address astigmatism. founding father Benjamin Franklin cut two different lenses in half and pieced them together to invent the bifocal, a one-pair solution for those with both near- and far-sighted vision impairments. But as the popularity of these lenses grew throughout the Renaissance, stabilizing extensions fashioned from wood, leather or animal bones were added to rest the lenses on the ears, resulting in the hands-free eyeglass framework we know today. The earliest glasses, used primarily by monks, were either handheld or perched on the nose. The history of eyeglassesīack in the 13th century, Italian glassblowers discovered that they could create crude glass lenses of different thicknesses that would add or subtract from the eye’s focusing power to compensate for these vision problems.Īs they came to understand the physics behind flawed vision, three types of handblown lenses evolved:Ĭoncave lenses : Thick at the perimeter and thin at the center, the concave shape moved the eye’s focus back toward the retina screen to correct nearsightedness (myopia).Ĭonvex lenses: Like a magnifying glass, these lenses are thickest at the center, moving the eye’s focus forward from behind the retina to correct farsightedness (hyperopia).Ĭylindrical lenses: The thicker/thinner portions of these lenses are asymmetrical, designed to correct astigmatisms. LOOKING FOR YOUR OWN PAIR OF EYEGLASSES? Find an eyewear store near you. This is where eyeglasses enter – and alter – the picture. Makes a movie theater look pretty simple! However, if the projector boys focus your views in front of your curved retina screen, your distance vision will be impaired, a condition we call nearsighted or myopia.Ĭonversely, if your projection team focuses your views behind the retina, items close to you will appear indistinct, a condition that’s called farsighted or hyperopia.Īnd if the cornea itself is misshaped, it can blur our vision by forming a second focal point, a condition we call astigmatism. If your pupil and cornea adjust all incoming light to focus clearly on your curved retina backscreen, you enjoy perfect vision. To further complicate the vision challenge, light must pass through the pupil and the curved transparent outer surface of the eye called the cornea, which together shrink and curve incoming images to focus them onto the eye’s back surface, the retina, which is also curved. Our earliest optometric pioneers discovered that how light bends as it enters the eye is key to how well we see. ![]() We can observe the dynamics of refraction most clearly by dipping a pencil into water and observing how it no longer appears straight. Refraction is the term given to how light slows and bends when it passes from a light-density medium such as air into the thicker density of transparent glass or plastic. The ancient Romans were first to discover that by employing pieces of glass to change the refraction of light, they were able to read small print more clearly, inventing the magnifying glass in the process. The sight of eyeglasses on our family, friends and co-workers is so common today that it’s easy to underappreciate the life-changing role that this simple, vision-correcting technology plays in our daily well-being.
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