What Does It Mean to be Farsighted?
Farsighted is another term for hyperopia. This means that the uncorrected eye is focused at a distance beyond 20 feet. For small amounts of hyperopia this results in great distance vision. As the amount of hyperopia increases, near work (computer and reading) becomes more difficult. For larger amounts of hyperopia, images have to be too far away to focus. For larger amounts of hyperopia there is no useful distance images focus at.
Younger patients are able to use the ciliary muscle to focus through hyperopia to see. As the ciliary muscle flexes, it changes the shape of the lens. The change in shape allows images to be focused at closer distances. If an eye is naturally focused at 30 feet, flexing of the ciliary muscle can change the focused distance to 20 feet. If the muscle flexes harder, it can focus images at 16 inches or closer depending on the patients' age and focusing ability.
For every year of life, the lens in our eye becomes larger. When the lens is larger, the ciliary muscle has to flex harder to create the same effective power. When we reach our 40's the lens in the eye becomes so wide in diameter that the ciliary muscle is no longer able to change the shape of the lens by flexing on it. This is when bifocals, no-line bifocals or readers become necessary for near work.
Be able to see past 20 feet is great for driving or recognizing images in the distance, but it does strain the eye more when an image gets closer. Hyperopia makes reading and computer work more difficult. This is why some people may only need glasses when working on objects up close.
In hyperopia, images are focused past the retina. To focus images on the retina a convex lens is needed. A convex lens is thicker in the middle and thinner at its edges. Convex lens magnify. This is why patients with strong farsighted corrections appear to have big eyes when wearing glasses. This appearance of excess magnification can be significantly reduced using modern lens materials like high index lenses, aspheric lens designs, small round frame designs and thicker plastic frame designs to hide thicker edges.
Younger patients are able to use the ciliary muscle to focus through hyperopia to see. As the ciliary muscle flexes, it changes the shape of the lens. The change in shape allows images to be focused at closer distances. If an eye is naturally focused at 30 feet, flexing of the ciliary muscle can change the focused distance to 20 feet. If the muscle flexes harder, it can focus images at 16 inches or closer depending on the patients' age and focusing ability.
For every year of life, the lens in our eye becomes larger. When the lens is larger, the ciliary muscle has to flex harder to create the same effective power. When we reach our 40's the lens in the eye becomes so wide in diameter that the ciliary muscle is no longer able to change the shape of the lens by flexing on it. This is when bifocals, no-line bifocals or readers become necessary for near work.
Be able to see past 20 feet is great for driving or recognizing images in the distance, but it does strain the eye more when an image gets closer. Hyperopia makes reading and computer work more difficult. This is why some people may only need glasses when working on objects up close.
In hyperopia, images are focused past the retina. To focus images on the retina a convex lens is needed. A convex lens is thicker in the middle and thinner at its edges. Convex lens magnify. This is why patients with strong farsighted corrections appear to have big eyes when wearing glasses. This appearance of excess magnification can be significantly reduced using modern lens materials like high index lenses, aspheric lens designs, small round frame designs and thicker plastic frame designs to hide thicker edges.
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