The eye is similar to a camera in its basic operation. There are three basic parts of the eye: a light focusing system, an automatic aperture system, and a light-sensitive detection system. Hypermetropia and Myopia, both are refractive defects in vision.
Myopia is the term for nearsightedness. Myopia results when parallel light is focused in front of the retina. Only objects closer to the eye have a clear vision and can be properly focused on the retina. This defect is most usually linked with an elongated eyeball.
Myopia is also known as nearsightedness.
In myopia, a person is not able to see distant objects clearly.
In this defect, the lens is not able to produce a sharp image of the distant objects on the retina. Instead, the image is formed in front of the retina.
The reduction in the focal length of the eye lens is the cause behind it. Elongation of the eyeball also causes Myopia.
Myopia can be corrected by using a concave lens of suitable focal length.
Hypermetropia due to a short eyeball, causes parallel light to be focused behind the retina. This happens if the cornea does not refract the light enough. People suffering from hyperopia have blurred vision of near objects and a clear vision of farther objects.
Hypermetropia is also known as farsightedness.
A person cannot clearly see the nearby objects as the image is formed behind the retina.
The increase in focal length of the eye lens may be a cause.
It may also be caused due to flattening of the eyeball.
Hypermetropia may be corrected using the convex lens of suitable focal length.
They can be cured by refractive surgery, glasses or contact lens. If you're nearsighted, your glasses or lens will be prescribed by a minus sign and a positive sign if you are farsighted. A refractive surgery will eliminate the need for glasses or lens. LASIK is the most common refractive surgery performed. In this surgery, some cornea tissues are removed by the laser after placing a thin flap on it. Phakic IOL is implantable lenses which are another surgical option for correcting nearsightedness.