Essay Example on The five senses humans Have

The ciliary body is all around the eye and contains zonules which are thin attachments that connect it to the lens Muscles in the ciliary body allow the lens to change shape which causes refraction of light Refraction can be defined as the bending of light rays as they pass through the tissues of the eye Accommodation occurs when the eyes focus on an object from near or far This process decreases as people get older The area behind the lens is called the vitreous chamber It contains a soft material that gives the eye its shape If this area is damaged blindness may result The optic nerve is the part of the eye that sends impulses to the brain The macula is next to the optic disc and is oval in shape It contains the fovea centralis which is made of cones and is the area where the clearest vision occurs If the macula or fovea centralis is damaged blindness may result A cataract can be classified as a degenerative eye disease however it is possible to be born with cataracts For a cataract to form protein in the lens builds and clouds vision Other ways this disease can occur is from trauma diabetes mellitus and chronic corticosteroid usage Cataracts can easily be seen with an ophthalmoscope and with the human eye This can be fixed by removing the lens via surgery and replacing it with an artificial lens Glasses or contacts can also be worn to improve vision 

The wet form can be treated with laser photocoagulation This disease is one of the most common causes of blindness in the elderly Nystagmus is a condition in which one or both eyes make uncontrolled and repetitive movements Brain tumors can be a cause Separation of the retina from underlying tissue within the eye is a disease called retinal detachment This can occur in several ways including trauma bleeding infection or tears in the retina This condition can cause flashes of light to be seen or photopsia Small tears can be treated by photocoagulation and cryotherapy More severe tears require a scleral buckle to be sutured to the sclera right over the separated portion Any misalignment of the eyes is termed strabismus A weak eye muscle does not allow the eyes to look in the same direction There are different forms depending on which way the eye deviates Esotropia is when the eye turns inward and exotropia is when the eye turns outward Hypertropia is an upward deviation and hypotropia is a downward deviation This condition may lead to diplopia in adults