When you wear contact lenses, you're in good company - more than 24 million people wear contact lenses in the United States alone. But have you ever wondered how these little plastic circles improve your eyesight? Read on for a closer look at contact lenses:
How the eye works:
To understand how contact lenses work, it's important to understand a little about how the eye works. When light is reflected from an object, it passes through the cornea (transparent patch) and pupil (the black part of the eye), and then the light passes through the lens, which focuses the light on the retina in the fundus. The retina is full of rods and cones that convert light into electrical impulses that are sent to the brain. Blurred vision occurs due to "refractive errors." In other words, the shape of the eye prevents light from hitting the retina directly, causing distortion.
How contacts correct refractive errors:
Contact lenses are miniature prescription lenses that float in "contact" with the tear film. Like glasses, contact lenses are damaged and focus light on the retina. There are different types of contact for different types of refractive errors:
Myopia (nearsightedness) is a condition in which objects that far away appear blurry and objects around them are clearly visible. This occurs when light enters the eye without proper focus, which is directly due to the shape of the eye. Standard green contact lenses such as Coopervision Avaira lenses can correct this very common condition.
Hyperopia (farsightedness) is the opposite of nearsightedness, in which objects around it appear blurry due to a slight focus along the retina. This condition also uses standard contact lenses that are available in all modalities.
Presbyopia is an age-related condition similar to hyperopia in that it causes blurring of objects. Presbyopia, however, has a different cause. While hyperopia is caused by incorrectly opening the eye, presbyopia is caused by the hardening of the lens in the eye, which eventually occurs in everyone as they age. Many with this condition require multifocal contact lenses such as B. Proclear Multifocals which can be adapted for short and long-distance prescriptions.
Astigmatism is a condition that occurs when the eye does not focus light evenly on the retina due to an irregular shape of the cornea or lens. To fix this, you need a special type of lens called a toric contact lens. To compare the difference between a lens correcting astigmatism and a lens correcting astigmatism, imagine the cross-section of two types of spheres. Aspherical lens, a lens that does not correct for astigmatism, can be represented as a simple section of a beach ball, whereas a toric lens, a lens that corrects astigmatism, is like a cross-section of a soccer ball. Since toric lenses must be aligned in a certain way, they must be carefully designed to be stable and accurate. A great example of this type of lens is the Biofinity Toric.
Contact lenses have come a long way since the first contact lenses were worn in 1801 by scientist Thomas Young, who attached the lenses to his eyes with wax. Advanced research and technology has greatly improved contact lens design and lens materials, which has helped increase the number of patients who can see clearly again without unnecessary glasses. If you want to learn more about how contacts work