 A contact lens is as its name suggests, contact between the eye and the lens. A lens is mainly used in eyes to improve its vision. The Corrective lens is also designed to do the same. In many human being due to the mismatch of the eye length and the refractive power of eye a problem is caused that is called refraction error. Normally a contact lens is used to minimize this refraction error and permits to the light to focus correctly on to the retina. Some of the conditions those can be removed by using contact lenses are:
1. Myopia: It is also known as the Near Sightedness or shortsightedness. In this refractive type of defect the images are made after the retina by the collimated light. The persons who are suffering from myopia can clearly see the nearby objects but can’t see the objects clearly which are situated at some distance. In this condition the long eyeball or the steep cornea focuses in the vitreous (means inside the eye) rather to create on retina.
2. Hypermetropia: It is also known as the Farsightedness. This is the exact opposite condition of Myopia. In this defect the person can see the far objects easily but nearer objects are hard to notice. In this defect the cornea is flat and the eye is short and they produce images before the retina.
3. Astigmatism: This is also an eye’s defect generally caused due to the irregular shape of cornea, but may be sometime due to the irregular shape of lens situated behind cornea the lenticular astigmatism can occur. Due to the oval shape the collimated light focuses on the two points rather than one which are placed back of the eye .
4: Presbyopia: This is a problem in which lens’s ability to focus is lost completely. And in this condition the people have to adjust their holding materials far from their normal position.
The persons who daily wear the contact lens should take off their lense the end of the day daily or in some-2 days depends upon the contact lens’s brand. Recently it is heard that, myopia’s problem can be corrected by the method Deliberate Overnight Flattening of the cornea. After it the eyes can be left without a lens or the eyeglass during the day. Normally the persons who are suffering from certain color deficiencies, a Contact lens named as a red tinted X-Chrome can be used. Neither these problems can be omitted completely by using the contact lenses nor it can store the normal visions , but it allows a little colorblind objects to distinguish their colors in a better way. There are some lenses which have shown some problems. Like, ChromaGen lens have shown problem in their vision at night, but it is a nice lens for the problem of color blindness. Before some time there was a study regarding the lens works it is noticed that the patients who have used the ChromaGen lens had shown their satisfactory in the eye problems like color vision, dyslexics in random, double-blind and placebo control. In the Placebo control and significant improvement is shown in the reading ability without the lenses.
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