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The ability to see is dependent on the actions of several components in and around the eye.
When looking at an object, light rays are reflected from the object to the cornea. The lights rays are refracted and focused by the cornea and the lens. The lens allows the light rays to focus sharply on the retina, and results as an upside-down image. The retina then converts the light rays into electrical impulses which are transmitted through the optic nerve to the brain. The brain translates the image and the result is an image in the upright position.
The human eye is similar to a camera. A camera needs a lens to focus an image and film to produce an image. In that way, the eye needs a lens (cornea, lens) to refract and focus light and a film (retina) on which to focus the light rays. If any one or more of these components is not functions properly, the result is a poor image. The retina, representing the film in a camera, captures the image and sends the picture to the brain to be developed. The macula is the highly sensitive central area of our retina that is responsible for our central focusing vision. It is the most used part of the retina
MYOPIA: Nearsightedness
Myopia, also known as nearsightedness is when the light entering the eye focuses in front of the retina rather than on the retina. Nearsighted people typically see well up close but poorly at a distance. This is caused by the eye being longer than a normal eye.
HYPEROPIA: Farsightedness
Hyperopia, also known as farsightedness, is when the light entering the eye focuses behind the retina rather than on the retina. Farsighted people typically have difficulty seeing up close and at a distance. This is caused by the eye being shorter than a normal eye.
ASTIGMATISM:
Astigmatism is when the front surface of the eye called the cornea is oval like a football rather than spherical like basketball. The cornea has 2 points of focus, a steeper point and a flatter point that causes light to focus at one or more points onto the retina, resulting in blurry vision for distance and near.
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