Cataract

• Causes of illness

• Symptoms and types Diagnostics

• Treatment and prevention

Causes of illness

Cataract – the eye disease which main sign is turbidity of the main substance or a crystalline lens capsule (decrease in their transparency), being accompanied visual acuity fall. In translation with Greek, the word "cataract" means "falling" or "falls". Ancient Greeks believed that gray color of a pupil at a cataract represents a film which, like falls, falls from top to down (falls) on a pupil, as a result of depriving of the person of sight.

At the expressed turbidity of substance of a crystalline lens the pupil gains gray color.Visual acuity depends on transparency of optical environments of an eye which provide formation of the accurate image of subjects on a retina, safeties of the visual and nervous device of a retina and the carrying-out ways bearing visual impulses in the visual centers of a cerebral cortex. If in any of these links there are pathological changes – result will be this or that extent of decrease in visual acuity.

The cataract causes decrease in visual acuity due to development of pomutneniye in substance of a crystalline lens. The crystalline lens is one of the most important components of optical system of the eye which main function is carrying out light and focusing of the image of subjects on a retina.

The cataract is one of the most widespread diseases of an eye. Among congenital pathology of an eye the cataract also occupies one of the first positions.

Prevalence of an age cataract in various countries and world regions significantly differs. It contacts the mass of factors: racial accessory, nature of food, impurity of environment, composition of drinking water, district level above sea level, heredity, etc.

Now around the world researches of the reasons and mechanisms of development of a cataract are intensively conducted. It is especially actual because the cataract is one of the main reasons for a reversible blindness. After all to prevent cataract development much more simply and the cheapest way, than for years to carry out its conservative treatment, or to carry out expensive surgical intervention.

The main success in this area is achieved in studying of the physical and chemical processes leading to violation of optical properties of a crystalline lens.

At a senile cataract there are changes of a chemical composition of a crystalline lens. In an initial stage of development of a cataract the content of water increases, the imbalance of a number of ions, amino acids accrues, the amount of water-soluble proteins and vitamins, ATP at the same time decreases. Besides, activity of a number of the enzymes participating in process of a metabolism in a crystalline lens decreases, oxygen consumption sharply decreases, processes of perekisny oxidation of lipids, etc. are broken.

Now the mechanism of free radical oxidation is the main reason of formation of a cataract.

Free radicals – the chemical compounds possessing high reactionary ability. In an organism they are constantly formed at a metabolism, however collapse special enzymes and natural antioxidants. Free radicals are very dangerous – they lead to destruction of cellular membranes and finally cause death of a cage.

In tissues of an eye the most essential additional factor stimulating formation of free radicals, light, in particular short-wave part of a range in the range of 200-300 nanometers is.

Education of free radicals in a crystalline lens is resulted by education and accumulation of the toxic connections leading to irreversible changes of proteins.

Special role the decrease fact in a crystalline lens plays with age activities of enzymes of antioxidant protection and reduction of concentration of natural antioxidants (vitamins A, E, glutathione, etc.).