The major eye structures include:
Cornea is a clear, thin tissue that covers the surface of the eye. It is extremely sensitive and contains numerous nerve cells.
Lens of the eye allow the refraction of light to occur. These clear tissues are usually bent, so that when the rays of light can be focused to one specific point on the retina.
Retina is a tissue found towards the back of the eye that is layered with multiple sensory tissues. Millions of photoreceptors that are found in the retina capture light rays and convert them into electrical impulses.
Optic nerve is a pathway for the electrical impulses to travel through to the brain from the retina. The electrical impulses by the rays of light are sent to the brain through the optic nerve and are portrayed by the brain as images.
Lasik surgery begins with the removal of the top layer of the cornea. Afterwards, the doctor uses laser to steepen or flatten the tissue of the eyes. This process in done in order to make sure that the eye is adjusted so that the lenses of the eye bend to focus on a point on the retina. After reforming the eye tissue, the removed layer of cornea is placed back to heal by itself.
Usually, when a person has a 20/20 vision, the refraction of the light through the lenses is focused exactly on the retina of his/her eyes. However, the refractive defect causes nearsightedness, or farsightedness to occur. Myopia is when the refraction of the light does not quite reach the retina of the eye. Because of this, one cannot see distant objects clearly. On the other hand, hyperopia is the exact opposite of myopia. When a person has a refractive defect of hyperopia, the refraction of the light focuses on a point far beyond the retina. Therefore, he/she cannot see close objects clearly.
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