FEMALE VOICE 1: Let's review how the eye works and what causes our vision to be naturally blurry.
MALE VOICE 1: The human eye works on the same principles as a camera. Light rays pass through the cornea onto the human lens creating a precise focal point directly on the retina. The retina is like the film in a camera. The image focused on the retina is sent through the optic nerve to the brain where the image is seen. When a person is either nearsighted or farsighted the visual disorder is usually called refractive error.
Myopia usually occurs when a person's cornea is too steep and / or their eye is too long in shape. This irregularity causes light rays to be bent at an irregular angle causing the lens to improperly focus the image on the retina. When a person is farsighted the opposite effect happens. Hyperopia or farsightedness usually occurs when the cornea is too flat and / or their eye is too short in length. Since light rays are irregularly angled the human lens improperly focuses an image onto the retina.
Those who are astigmatic are unable to focus clearly at any distance. This is caused by an asymmetrical or uneven curvature of the cornea. The astigmatic eye is shaped more like a football, unlike the normal eye which is more shaped like a basketball. This uneven spherical shape does not allow the eye any single point of focus resulting with some images that seem partly in focus while others seem partly out of focus.
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