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News » Vision problems: diseases that compromise the regular functions of our eyes
Vision problems: diseases that compromise the regular functions of our eyes
The activities regularly carried out by our eyes are very straightforward: in an absolutely normal conditions, then in the absence of defects of vision, light rays coming from the outside through the various ocular transparent structures to be collected and then focused on the retina .
This, with its infinite corollary of point sensory cells, is transmitted through the optic nerve to the brain, which processes the information from the two eyes turning these in a single visual impression.
The main optical structures delegated to this extraordinary work are the lens and the cornea. also they involved the tear film and the pupil. The first, made up of tears, keeps the cornea transparent and homogeneous, making them take a mirror and look shiny.
The pupil, instead, adjusts the amount of light entering the eyeball to do, by decreasing or increasing the diameter.
But what happens if any of these organs see compromised, for various and sundry reasons, your own business? In these cases normal mechanism described jams here is that you speak of the presence of defects of the view that making the necessary remedial action consisting in the use of eyeglasses or, in severe cases, surgery.
The defects of the most common views
Myopia is undoubtedly the most common defect of view, considering that in Italy is affected approximately 25% of the population.
It consists of a refraction anomaly caused by a longer than normal eye.
The myopic eye, in fact, focuses on distant objects in front of the retina, thus the viewer perceives blurred. Up close, however, the objects are put clearly focused.
Generally, the defect is corrected with biconcave lens (divergent).
Hyperopia is another defect of the view, however caused, in this case, by the presence of a shorter than normal eyeball. The hyperopic eye focuses the image beyond the retina.
In contrast to the short-sighted person, the hyperopic clearly see distant objects but found it difficult to see their neighbors.
If the problem is mild, such a defect of sight tends to offset course, in other cases, however, is corrected by biconvex lenses (converging).
Presbyopia is that disorder characterized by a gradual and progressive loss of the ability to focus up close image. This is due to the reduction of elasticity of the lens which makes inevitable the greater difficulty of accommodating.
In this situation, the minimum distance at which an object is brought into focus tends to move away. That\'s why, for example, older people read the newspaper, holding more distant from the eyes. It is estimated that already after the 40 years it becomes, in most cases, require the use of reading glasses.
Astigmatism is instead that defect of vision that results in a lower sharpness caused by a deformation of the cornea or deterioration in the internal structures of the bulb.
Nell\'astigmatico, often, the cornea is not perfectly spherical, presenting radii of curvature in different meridians. The images on the retina, therefore, is present in a deformed manner.
The correction of this disorder occurs with the use of cylindrical lenses.
spread less, compared to the ones mentioned, it is the defect of the defined color blindness view, this a condition characterized by an altered perception of colors.
Generally, it is of genetic origin, but can also be acquired as a result of trauma.
Again, a bit \'as in all fields pertaining to the smooth functioning of our body, it is advisable not to overlook the anomaly and intervene in time in order to prevent such a defect of the worst offenders.