Types and types of contact lenses

To restore visual acuity and provide comfort modern room lenses help. Kinds of them are subdivided depending on a material of manufacturing, term of replacement and other factors. Due to such a large classification, everyone can choose for themselves the best in quality and price option. And to make the choice easier, we suggest that you learn more about what contact lenses are (types and types). Also, you will learn how the selection procedure works and study the care recommendations.

A bit of history

Contact lenses, like glasses, are a non-operational method of vision correction. For the first time, Leonardo da Vinci started talking about them in the beginning of 1500. After 387 years of the glassblower and Germany, Müller produced a glass lens that could be placed in the patient's eye. Since then, several attempts have been made to create not only high quality, but also comfortable contact lenses.

In 1960, the first soft lenses appeared and in 10 years their mass production was established. Over the years, various leading companies have developed new technologies and creations, as well as materials and appearance of the surface, it became possible to wear a lens without removing it without damage to health and so on.

Today's market offers a lot of options for lenses, designed not only to correct vision, but also to change the natural shade of the cornea. But despite this, each brand tries to expand the line even more for the convenience of its consumers and does not stop the development of new species. For example, today the types of contact lenses Akuyview are:

• For people with myopia or farsightedness - one-day, prolonged wearing, for sports, reusable, two-week, for correction and shine;
• For people with astigmatism - one-day and two-week.

Types of contact lenses

To date, there is a classification of such characteristics:

• Depending on the material of production: soft and hard;
• By the term of replacement: daily, frequent scheduled (after one or two weeks), planned (in a month, a quarter, six months);
• From the mode of wearing: day, flexible, prolonged and continuous wearing;
• Special purpose: sclerotic, orthokeratological, hybrid;
• Cosmetic: color and color.

Soft contact lenses

Soft contact lenses are the most common kind. They are prescribed to people with farsightedness, nearsightedness, astigmatism and senile far-sightedness. They can also be used for medicinal purposes (for example, when there is a need to apply drugs or protect them to speed up the healing process).

Their advantages:

• Comfort in wearing;
• Ability to absorb moisture;
• Ability to pass air;
• They are not felt on the retina.

Types of soft contact lenses:

• Hydrogel - they contain a high percentage of moisture, and the surface is very smooth, elastic and elastic;
• Silicone-hydrogel - are characterized by a high oxygen permeability, and they also keep the shape well.

This type is not used in the presence of defects in the shape of the cornea. Due to its elasticity, the lenses do not have the proper effect. The disadvantage of such lenses is that when dried they become hard and brittle, so they can be stored only in a special solution. They also require careful handling, because they can easily tear.

Rigid lenses

Rigid contact lenses are prescribed by ophthalmologists in those cases when the patient has a change in the shape of the cornea, which can not be corrected by a soft kind. This can be, for example, astigamism. The process of adaptation to them takes some time. At the very beginning of wearing they are felt before our eyes. Especially it is felt at blinking. The main feature of hard contact lenses is that they are manufactured in special laboratories according to the individual parameters of the patient, since it is necessary to accurately match the inner surface of the lens to the cornea.

Types of contact lenses for the eyes of a hard type:

• Gas-tight - oxygen does not penetrate through them;
• Gas permeable.

Advantages of such lenses:

• More durable;
• Keep the shape well;
• Give a clear and clear image;
• Easier to clean from contaminants.

According to statistical data, only 10% of patients worldwide have hard contact lenses. The remaining 90% use soft.

The hard type is prescribed in severe forms of astigmatism and keratoconus. In the process of creating such lenses, more rigid materials are used. They first feel in front of each blink and the process of getting used takes time. But this type perfectly retains its shape and is durable, and still, as a rule, does not cause allergic reactions, since deposits on hard lenses are formed more slowly than in the case of soft lenses.

By deadline of replacement

The term of replacement of contact lenses is the period of time established by the manufacturer, in which contact lenses can be used. Upon expiration, the old pair must be replaced with a new one.

By the term of replacement, there are the following types of contact lenses for the eyes (photo-examples above):

• Daily replacement: every day you need to put on a new pair. This kind provides maximum comfort, and also guarantees high hygienic use. The disadvantage is the high cost.
• Frequent scheduled replacement : the frequency of putting on a new pair is one to two weeks or one month. This species is optimal in terms of price and hygienic use. You can wear the lens for several days without removing it.
• Planned replacement. They are divided into monthly, quarterly and semiannual. This is the most economical option. Despite the fact that they are resistant to the formation of protein and protein deposits, the deposition of microorganisms, in order to achieve a high level of hygiene, it is necessary to use quality solutions for their purification. Such contact lenses do not provide for the possibility of continuous wear for more than a day and it is recommended to remove after 15 hours.

It is necessary to replace all types of contact lenses after the specified replacement period. Both their properties and the level of hygiene are reduced after a certain time, and this affects not only the quality of the image, but also the health of the eyes.

By wearing mode

This is not the same as the replacement period. Wearing mode implies a maximum period of time during which contact lenses can not be removed. It is due to certain characteristics of the material from which they are made, as well as the period of replacement.

The wearing mode can be of the following form:

• Day (DW): the lenses are worn in the morning and taken off at night;
• Flexible (FW): allows in such a pair of lenses to sleep one or two nights;
• Prolonged (EW): contact lenses of this type can be worn for up to six days without removing;
• Continuous (CW): the wearing mode without removing is increased to thirty days.

The latter mode of wearing appeared when, during the manufacture of contact lenses, rigid gas-permeable and silicone-hydrogel materials began to be used. They provide a high level of oxygen permeability.

To prolonged and continuous mode of wearing are frequent scheduled replacement of contact lenses. Types of lenses scheduled replacement are characterized by a daily and flexible periods.

Cosmetic contact lenses

Cosmetic lenses were originally designed to correct various congenital or acquired eye defects (eg, corneal opacities). To date, they are used to change the natural color of the eyes and create an unusual image.

Cosmetic lenses come in:

• Colored;
• Coloring.

Both those and others are produced both with optical power, and without it.

Color contact lenses completely change the color of the eyes or enhance the saturation of the natural shade. The pupil's area remains transparent, so that the quality of the image is preserved. Previously, the range of such products was limited only by the color palette.

Types of colored contact lenses:

• Colored: densely colored lens with an imitation of a complex pattern of the iris of the eye. Allow to turn rich brown eyes into honey-tea or soft-violet. There are one-day and prolonged wearing. The color palette is very diverse and has a huge number of all kinds of shades.
• Crazy (carnival) lenses: differ in a variety of color patterns and effects on the iris zone. Very popular during holidays such as New Year and Halloween, as well as various themed parties and comic-kones (a festival dedicated to comic book superheroes). They are also popular with theater artists. The choice of such lenses amazes with its diversity. You can find emoticons, a chessboard, neon eyes or turn into a cat, a vampire, a witch and so on.

Tinted contact lenses differ from color ones by the degree of color saturation. They do not completely change the color of the iris, but can only enhance the natural shade of the eyes. To such contact lenses, the pupil zone is also colored. But this is not affected by sight. After all, the degree of coloration is so weak that a natural iris pattern can be seen through the lens.

Special contact lenses

Scleral lenses are used in rare cases when the patient has an irregular shape of the cornea, a "dry eye" cider, keratoplasty was previously transferred, and so on. In this case, a space appears under the lens, which is filled with tear fluid. This kind is made individually for each and is divided into corneoscleral, semi-scleral, miniscleral and scleral.

Orthokeratological contact lenses are expensive, difficult to select and labor-intensive, and also necessary in keratotopograph (special equipment). This type is designed to correct myopia up to six diopters, as well as myopic astigmatism up to 1.75 diopters. Suitable for athletes, people who work in dusty rooms and so on.

Hybrid contact lenses are used in cases where a patient needs a hard type, but there is an individual intolerance. Currently, they are also prescribed to correct high-grade astigmatism and keratoconus.

How to decide the choice?

Modern technologies allow creating new kinds of contact lenses. Which is best advised only by an ophthalmologist. It conducts the necessary procedures and determines the parameters that affect the choice of lenses. The doctor prescribes a prescription for you and, based on your lifestyle and needs, recommends several types of contact lenses.

During the examination, parameters such as the visual acuity of each eye, refraction, the state of accommodation and the fundus, the thickness and shape of the cornea and so on are determined. The accuracy of all data depends not only on the patient's quality of vision, but also on how comfortable it will be for you to use separate types of contact lenses. For ophthalmoscopy (examination of the fundus of the eye) and measurement of the radius of curvature, for example, it is important to have the necessary equipment, which allows complete research. So, in order to use contact lenses it was comfortable and they did not cause any irritation, a visit to the doctor is always a condition.

After the examination, the doctor gives recommendations on the choice depending on the patient's profession, his hobbies and so on. For example, drivers of vehicles are suitable lenses that can not be removed at night and do not require special care. And people who spend a lot of time in front of a computer monitor, need those who have increased gas permeability. Such a lens does not allow drying out the mucous membrane of the eye and prevents possible irritations.

In conclusion, the doctor suggests any kind of contact lenses depending on all the above parameters and financial capabilities of the patient, and also teaches the use and gives advice on how to care for them.

With the correct selection of contact lenses from time to time, you must visit a doctor. Perhaps some of your settings have changed and you will need to change the recipe.

Recommendations for care and use

• Before each donning and removing the lens, you should wash your hands with soap and water.
• Makeup is applied after the lenses are worn.
• Always use a new solution and monitor the expiration date.
• The container is replaced every three months.
• Each time when removing contact lenses, they must be carefully cleaned under a stream of water or solution.
• Use a special tweezers. It does not damage the lens.
• For various damage to contact lenses, they need to be replaced.
• You can not store two lenses in the same container cell.
• It is not recommended to swim in lenses, as they can be washed off by water.
• The solution is poured into a container, and then lenses are placed in it.
• The contact lenses left without solution quickly dry out and deform.

If you adhere to the above and other recommendations prescribed by your ophthalmologist, the use of contact lenses in everyday life will be comfortable and not harmful.