Usually implies a more or thornless severe clouding of a transparent shell, or environment of the eyeball that lies in the path of light rays and prevents vision. Currently, doctors call a thorn almost exclusively stain the cornea. As is usually the consequence of previous inflammation of the cornea, its spots are a great variety in shape, size, color and turbidity intensity.
In regard to the latter it should be noted that althoughthere are countless transitions from subtle loss of transparency of the cornea to its full opacity, but, in general, distinguish the following forms of spots:
- spot, more or less limited and usually pearly,
walleye, which always is a scar remaining after the preceding whatever was corneal ulcers.
The spots of the cornea, therefore, walleyecan occupy not only the entire area of the pupil, but these or other parts of it, and accordingly, in connection with the degree of loss of tissue transparency is modified their significance for the act of vision. In general, they all cause a decrease in the severity of it, but in varying degrees and forms.
Thus, for example, poured, or semitransparenttranslucent haze more impaired vision than sharply limited, but occupy only a portion of the pupil opaque stains. It depends on the fact that when the translucent spots of light rays passing through the darkened space, scatter light in different directions on the retina and thus weaken the difference in the brightness of the subject image and deprive it of clarity, causing at the same time painful, sometimes painful for the patient's sense of "blinding ".
If the cataract is opaque and takes onlyof the pupil, the delaying of the light rays, it only weakens the image brightness of the subject, even though the latter retains the clarity of the image. If the spot to take the whole pupil, the patient can only remain weak light feeling. If an opaque stain sits in the center of the pupil, the eye is improved by the expansion of the latter (in low light); on the contrary, the vision is improved by narrowing the pupil (in bright light), if the cataract is located on the edges of it.
The decline of view, existing at the spots of the cornea,entails a whole series of other serious for the patient's seizures: severe myopia, the so-called accommodative asthenopia and even spasm of accommodation, ie, involuntary contractions of the ciliary muscle, and articles submitted sometimes extremely enlarged... Binocular vision is often quite impossible, etc. Furthermore, it can develop muscular asthenopia, strabismus, and the children -.. Even involuntary trembling eyes.
The prognosis of corneal spots depends on agesubject, duration, location and nature of the cloud; than the spot less fresh and more superficial, the prediction is favorable. Old stains caused by scars, incurable. But the younger is very difficult to treat, usually appointed by irritating agents, whose main task - to enhance the metabolism of the cornea and to facilitate the absorption of morbid products.
Operational techniques, scraping or cuttingspots, rarely lead to the goal, and even pose a risk of deterioration of the disease. They are relevant only for superficial spots caused by the deposition of lime or lead salts. But if the operational techniques rarely possible to achieve the removal of stains, the improvement and even recovery of operation sometimes fails iridectomy (formation of an artificial pupil), which gives an insight into the eye light rays. Further, good service often have so-called "stenopeicheskie glasses" - the opaque plate with a small hole in the middle, through which you can open access light rays through the intact cornea. However, these glasses are only useful when viewing smaller objects close.
Finally, one of the treatments for cataracts isa tattoo it as a cosmetic purpose and in order to improve view. The process of tattooing is that using a special tool consisting of several needles, injections walleye and then place them in a special spatula rubbed Chinese ink. Destruction sharp difference of color walleye from neighboring healthy tissue is achieved by a cosmetic purpose of the operation; elimination of producing "blinding" spots translucency improves vision of the patient, ie. e. the task is achieved by therapeutic operations.