In the contact lens has a rich history that begins more than 500 years ago. I think people always want to see good, and it does not wear glasses. Development of technology that would make this possible, was only a matter of time.

Story

For the first time I described the idea of ​​contact lenses, and made them an outline of none other than Leonardo da Vinci - even in 1505. It inspired the immersive experience of their own eyes in a cup of water.

Over a hundred years later, Rene Descartes also proposed the idea to put the lens on the cornea. However, he developed lenses were impractical - a man who would wear them, could not blink.

The history of contact lenses has continued in 1801, when Thomas Young has improved the development of Descartes. In 1827 Sir John Herschel suggested the idea to create a lens that would be ideal to lay on the surface of the eye. After that, the development of contact lenses has gone much faster in 1888 and they have already started to test as a means for vision correction.

With the invention of breathable materials and soft lenses in the 1960s - 1970s, the lenses are safer and more convenient. Their popularity among people with myopia Myopia - when visual acuity falls   and hyperopia Hyperopia - than it is fraught?   grew rapidly. A little later there were contact lenses that can be used for astigmatism Astigmatism - lenses, glasses or surgery? . Due to their cost, hygienic benefits and ease of use became more popular disposable contact lenses.

Proceedings

Contact lenses (except for different colored lenses) are practically invisible when worn. First lenses were made of glass, causing eye irritation, and they can not be worn for long periods of time. With the advent of the lenses of polymethylmethacrylate lens wear it was much more comfortable, but they had a number of shortcomings. Specifically, these lenses are not passed to the cornea oxygen, causing many negative effects. In the late 20th century lenses were designed from materials that allow oxygen and the evaporation of the liquid is absorbed, so that they can safely be used in industrial areas. Such lenses are called hard and is used when a significant correction of vision.

Most popular, however, are soft lenses, which are made from a hydrogel or silicone hydrogel. Unlike hard lenses to soft lenses do not have to get used to - the person ceases to feel them almost immediately. Today, there are so-called hybrid contact lenses - for example, a small rigid lens can be placed on top of a large soft. This is necessary when using one type of contact lenses is impossible to achieve improved vision and comfort.

Silicone hydrogel contact lenses today are considered the most comfortable and safe. They have very good oxygen is passed, but may cause skin dryness and discomfort, particularly during long-term wear.

Wearing contact lenses

Contact lenses, in addition to material and other parameters, and different wearing regime. Lenses to be worn during the day must be removed before you go to bed. Contact lenses for extended wear, you can usually not be removed within a week. The newest materials such as silicone hydrogel allow to produce lenses that can be worn for up to thirty days. Typically, after this lens discarded and new wear.

Wearing contact lenses for a long time associated with an increased risk of various infections of the cornea - mainly because of the inability to properly clean the eyes and the stagnation of bacteria. The most common complications of lens wear for a long time is conjunctivitis; in some cases, possible allergic reactions Allergic reactions: how to understand why you tickle in the throat .

Eye ointment Dexamethasone Dexamethasone - one of the most effective glucocorticosteroids   produced by several manufacturers. As an example we can take dexamethasone ophthalmic ointment that makes the Belgian pharmaceutical company Alcon Couvreur-called maksideks. This ointment is used to treat many eye diseases.

The mechanism of action of eye ointment maksideks

Active ingredient ointment maksideks a glucocorticosteroid (GCS), dexamethasone - analogue of natural corticosteroids, which are produced by the adrenal cortex of man. Produced 0, 1% ophthalmic ointment maksodeks in the aluminum tube 3, 5 g (1 g of ointment contains 1 mg dexamethasone).

When laying the ointment of the lower eyelid active substance dexamethasone rapidly penetrates the surface layers of the eye and acts mainly locally, providing anti-inflammatory, anti-allergic, anti-edema effect. Under the influence of deksometazona there is a narrowing of the small blood vessels (capillaries) and a decrease in permeability, redness of the sclera passes, swelling, and all the other signs of inflammation or allergies. This occurs due to the fact that dexamethasone inhibits the formation, transport and activity of biologically active substances involved in these processes.

Like any other dosage forms of dexamethasone ophthalmic ointment maksideks not be used for a long time - it can lead to several side effects, including general, as part of yet dexamethasone into the bloodstream.

The main side effect of eye ointment maksodeks is its ability to significantly reduce the immune system, which often leads to the attachment of a bacterial or fungal infection Fungal infection: to prevent and defeat . Often this infection can not be noticed immediately as dexamethasone inhibits any inflammation.

Because of the risk of common side effects of the ointment is used to treat children and adolescents as well as dexamethasone is able to influence their growth and sexual development.

With which diseases and how to apply

Eye ointment dexamethasone maksodeks nonsuppurative prescribed for inflammatory and allergic processes in the eye:

• in inflammation of the surface layers of the eye - the edges of the eyelids, conjunctiva, sclera and cornea (blepharitis, conjunctivitis, scleritis and keratitis);
• in inflammation of the iris, ciliary body and choroid (iridotsiklitah and uevitah);
• for the prevention of inflammation after burns and eye after an eye operations (just after the defect surface layers of the eye is completely healed).

Ointment maksodeks for a lower eyelid in the form of a long strip from one half to see two or three times a day for a maximum of two to three weeks.

Contraindications

Contraindications for use of eye ointment maksodeks are:

• Hypersensitivity to the components of the patient maksodeks ointment;
• eye diseases with viral, fungal, bacterial or purulent tubercular nature;
• damage to the surface layers of the cornea;
• breast-feeding;
• childhood and adolescence - clinical studies of the drug in these group of patients have not been conducted.

During pregnancy, the use of eye ointment maksodeks possible only on prescription in the case, if the expected benefit to the mother's body exceeds the potential risk to the fetus.

Side effect

If you apply eye ointment prescribed by a doctor maksodeks short courses, the side effects usually do not happen. If ointment is used for a long time (more than ten days), it may cause side effects in the form of:

• the gradual development of glaucoma Glaucoma - a perspective possible blindness   - Persistent increase in intraocular pressure, which is accompanied by severe headaches;
• lesions of the optic nerve with visual impairment;
• clouding of the lens - cataracts Cataracts - how to solve the problem completely? ;
• slow healing of wounds - if the ointment is applied after injuries and burns;
• if the patient had corneal thinning, prolonged use of eye ointment maksodeks may result in perforation;
• as the ointment reduces immunity tissues of the eye, may join purulent bacterial or fungal infection, which is masked by dexamethasone, removes all the phenomena of inflammation;
• allergic reactions such as redness and edema - in this case the ointment immediately canceled.

Eye ointment maksodeks - is an effective drug, which, however, has many side effects, so it should be used only if prescribed by a doctor with all the indications and contraindications, and short courses.

Galina Romanenko