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 DEFINITION
There are alterations of the lenses of the eye, with the formation of the focus of vision in other places that are not in the retina, therefore the blurry vision takes place. They can take place well for alteration of the curvature of the cornea, or for different length of the eyeball.
- In the short-sighted person the image forms before the retina.
- In the long-sighted one he forms behind the retina.
DEFECTS OF THE REFRACTION
The most frequent defects of the refraction are:
Myopia - The length of the eyeball produces that the vision focus is realized ahead of the retina, especially in the background vision, for it a blurry vision takes place. On the other hand in nearby objects they do not take big problem as it popularly to the short-sighted person there is called he "I cut of sight".
It can be caused because the balloon of the eye is very long of ahead to behind or because the power of refraction of the lens is very strong.
The myopia generally develops in the school epoch and for 20 years it usually stabilize. Till then it can develop very quickly and need frequent changes of glasses or contact lenses. The same affects men that to women and there is a clear familiar predisposition.
- Symptoms:
- blurry vision of the distant objects
- squint
- headache
- ocular tension
Farsightedness - In her the eyeball is excessively short what produces an approach behind the retina. Also a blurry vision happens.
Astigmatism - In this affectation the curvature of the cornea is irregular what produces a distorted vision or of several simultaneous foci. He usually accompanies to the myopia or to the farsightedness.
Long-sightedness - For the age there are getting lost the capacities of approach of the ocular lenses, for it there are usually precise glasses for the reading. This problem affects persons between the 40 and 60 years.
DIAGNOSIS
A general examination of the eye or examination oftalmológico includes:
- test of visual keenness
- test of the refraction
- test of visibility of the color
- test integrals of muscles
- examination with light
- examination of the retina
TREATMENT
The myopia is compensated very easily with the use of glasses or contact lenses, depending every case and problem of refraction.
- Advantages: They do not have any effect on the eye.
- Disadvantages: Esthetics, sports, profession, baths, etc...
- The contact contact lenses:
- Advantages: Better visual correction than the glasses, esthetics, activities.
- Disadvantages: Intolerance to the same ones, corneal ulcers and sometimes serious infections, is essential a suitable hygiene.
The surgery is indicated in certain cases of myopia.
WHAT DOCTOR CAN TREAT ME?
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DEFINITION 
