What lenses are there?
For vision correction, in addition to glasses, contact lenses are widely used. They got this name because they are in direct contact with the eye. This is not to say that this is a recent invention, the brainchild of new technologies. We can talk about what lenses are today, but they were invented much earlier.
The history of contact lenses
For the first time contact lenses were described by Leonardo da Vinci at the beginning of the XVI century. In 1887, the first glass contact lens was placed on a person deprived of his eyelids to save his eyes from drying out. The experience was successful - the patient wore this lens for more than 20 years. In 1938 plastic glasses replaced the glass lenses. In the 50s of the twentieth century, a polymer hydrogel was synthesized, which is still successfully used in the manufacture of modern contact lenses. This gel has two unique features: the ability to pass oxygen (the eye “breathes”) and the ability to absorb and retain moisture, washing the surface of the eye. This gave impetus to the massive introduction of contact lenses in everyday life.
Even a simple listing of what contact lenses are in the modern world will take a lot of time.
- Let's start with the most simple - one-day. It is precisely for this reason that they are so called that they are worn for only one day, after which they are thrown away, and the next day they put on a new pair.
- The next view is daily lenses. These lenses are worn in the morning, and removed in the evening, giving your eyes a rest overnight. They can be used for two or three months, then they need to be changed to new ones, because worn lens edges can injure the cornea. In addition, during this time microorganisms and sediment appear on them, which makes the image cloudy, blurry. When wearing such lenses, you should do at least one “discharge” day a week, allowing your eyes to completely relax from the lenses.
- There are permanent lenses for long wearing - silicone hydrogel, they are usually worn without removing, for a very long time - up to 30 days.
- Decorative lenses change the color of the iris. They are divided into colored (overlapping own color of the eye) and tint (which simply make the natural color brighter). Tint lenses should choose “tone to tone”.Pale blue eyes with their help will become bright, slightly greenish will get a rich emerald color. But trying to put blue tint lenses on brown eyes is useless, because the result will be deplorable: an indistinct dirty-gray color will not exactly decorate the exterior. Colored and tinted lenses, in addition to the decorative function, can also correct the vision, if they have such a function.
By focusing on what lenses are, you can make an informed choice.
Indications and contraindications
In some cases, wearing contact lenses is the only way to correct vision, which cannot be corrected with glasses. Also, a direct indication for wearing them is too active lifestyle: sports (especially swimming, athletics, ball games) or work of this kind, where it is impossible to wear glasses (we sweat or glasses gather too quickly).
When moving from glasses to contact lenses, it is worth consulting with an experienced oculist to decide which lenses are best to choose: daily, regular or none at all if the doctor finds contraindications to the patient. You can not wear lenses to people with diseases of the eye, especially infectious, as well as after eye injuries. Sometimes such microtraumas occur just when using the lenses incorrectly.In this case, you should give your eyes a rest for two weeks and use glasses at this time.
Progress never stands still, and the same goes for the contact lens market. Their variety is so great that the lenses, which one can choose from different quality, from any material and in any price range, are able to satisfy the most demanding customers.
Date: 10.10.2018, 13:08 / Views: 95274
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