Modern room lenses help to restore visual acuity and provide comfort. Their types are divided depending on the material of manufacture, the replacement period and other factors. Thanks to such a large classification, everyone can choose for themselves the best option in terms of quality and price. And to make the choice easier, we suggest that you familiarize yourself in more detail with what contact lenses are (types and types). You will also learn how the procedure for their selection is carried out and study the recommendations for care.
A bit of history
Contact lenses, like glasses, are a non-surgical method of vision correction. For the first time, Leonardo da Vinci spoke about them as early as the beginning of 1500. After 387 years of glass blowing and Germany, Müller made 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 ten years later their mass production was established.release. Over the years, various leading companies have developed new technologies and creations, as well as materials and surface appearance, it has become possible to wear the lens without removing it without harming he alth, and so on.
Today's market offers a wide variety of lenses designed not only to correct vision, but also to change the natural shade of the cornea. But, despite this, each brand is trying to further expand the line for the convenience of its consumers and does not stop developing new types. For example, today the types of contact lenses "Acuview" are:
- for people with nearsightedness or farsightedness - one-day, long-term wear, for sports, multiple use, two weeks, for correction and shine;
- for people with astigmatism - one day and two weeks.
Varieties of contact lenses
Today, there is a classification according to the following criteria:
- depending on the material of manufacture: soft and hard;
- by replacement period: daily, frequent scheduled (in one or two weeks), scheduled (in a month, quarter, six months);
- from wearing mode: daily, flexible, prolonged and continuous wear;
- special purpose: scleritis, orthokeratology, hybrid;
- cosmetic: color and tint.
Soft contact lenses
Soft contact lenses are the most common type. They are prescribed for people with farsightedness, myopia, astigmatism and senile farsightedness. They can also be used for medicinal purposes (for example, when there is a need to put drugs in the eyes or protect them to speed up the healing process).
Their benefits:
- wearing comfort;
- ability to absorb moisture;
- breathability;
- 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 - characterized by a high rate of oxygen permeability, and they also keep their shape well.
This type is not used if there are defects in the shape of the cornea. Due to their elasticity, the lenses do not have the desired effect. The disadvantage of such lenses is that when they dry they become hard and brittle, so they can only be stored in a special solution. They also require careful handling as they can break easily.
Hard lenses
Hard contact lenses are prescribed by ophthalmologists in cases where the patient has a change in the shape of the cornea that cannot be corrected with a soft look. It can be, for example, astygamtism. The process of adaptation to them takes some time. At the very beginning of wearing, they are felt before the eyes. This is especially felt when blinking. The main feature of hard contact lenses is that they are made 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 hard eyes:
- gas-tight - no oxygen can penetrate through them;
- gas-permeable.
Advantages of these lenses:
- more durable;
- keep their shape well;
- give a clear and sharp image;
- cleans up dirt more easily.
According to statistics, only 10% of patients worldwide wear hard contact lenses. The remaining 90% use soft.
The hard type is prescribed for severe forms of astigmatism and keratoconus. In the process of creating such lenses, more rigid materials are used. At first they are felt before our eyes with every blink and the process of getting used to takes time. However, this type retains its shape perfectly and is durable, and, as a rule, does not cause allergic reactions, since deposits on hard lenses form more slowly than in the case of soft lenses.
By replacement period
The contact lens replacement period is the period of time set by the manufacturer in which contact lenses can be used. After it expires, the old pair must be replaced with a new one.
According to the replacement period, 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 type provides maximum comfort, and also guarantees high hygiene of use. The disadvantage is that it is expensive.
- Frequent scheduled replacement: The frequency of putting on a new pair is one to two weeks or one month. This type is optimal in terms of price and hygiene of use. You can wear lenses for several days without removing them.
- Scheduled replacement. They are divided into monthly, quarterly and semi-annual. This is the most economical option. Although 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 cleaning solutions. These contact lenses are not designed to be worn continuously for more than a day and are recommended to be removed after 15 hours.
All types of contact lenses must be replaced after the specified replacement period. Both their properties and the level of hygiene deteriorate after a certain time, and this affects not only the image quality, but also the he alth of the eyes.
By wearing mode
This is not the same as replacement time. Wearing mode implies the maximum period of time during which you can not remove contact lenses. It is due to certain characteristics of the material from which they are made, as well as the replacement period.
Wearing mode can be as follows:
- Day (DW): lenses are worn in the morning andrented for the night;
- flexible (FW): allows one or two nights of sleep with this pair of lenses;
- extended (EW): contact lenses of this type can be worn for up to six days without removing;
- Continuous (CW): Extended wear mode to thirty days.
The latest wearing mode came about when rigid gas permeable and silicone hydrogel materials were used in the contact lens manufacturing process. They provide a high level of oxygen permeability.
Extended wear and continuous wear include frequent scheduled replacement of contact lenses. Planned replacement lens types are characterized by daily and flexible periods.
Cosmetic contact lenses
Cosmetic lenses were originally intended to correct various congenital or acquired eye defects (for example, corneal opacity). Today, they are used to change the natural color of the eyes and create an unusual look.
Cosmetic lenses are:
- color;
- tinted.
Both of them are available both with and without optical power.
Colored contact lenses completely change the color of the eyes or enhance the saturation of the natural shade. The pupil area remains transparent in order to maintain image quality. Previously, the range of such products was limited only by the color palette.
Types of colored contact lenses:
- Colored: densely colored lens with complex pattern imitationiris of the eye. They allow you to turn rich brown eyes into honey-tea or pale violet. There are one-day and long-term wear. The color palette is very diverse and has a huge number of various shades.
- Crazy (carnival) lenses: distinguished by a variety of color patterns and effects applied to the iris area. They are very popular during holidays such as New Year and Halloween, as well as at various themed parties and comic-cons (a festival dedicated to superheroes from comics). They are also popular with theater artists. The choice of such lenses is striking in 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 colored contact lenses in 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. For such contact lenses, the pupil area is also colored. But it does not affect vision. After all, the degree of coloration is so weak that the natural pattern of the iris is visible through the lens.
Special Purpose Contact Lenses
Scleral lenses are used in rare cases when the patient has an irregular shape of the cornea, dry eye cider, previously had keratoplasty, and so on. In this case, a space appears under the lens, which is filled with tear fluid. This type is made individually for each and is divided into corneoscleral,semiscleral, miniscleral and scleral.
Orthokeratological contact lenses are expensive, difficult to fit and laborious, and require a 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 areas and so on.
Hybrid contact lenses are used in cases where the patient needs a hard type, but there is an individual intolerance. They are also currently prescribed to correct high grade astigmatism and keratoconus.
How to choose?
Modern technologies allow creating new types of contact lenses. Which one can only be advised by an ophthalmologist. It carries out the necessary procedures and determines the parameters that affect the choice of lenses. Your doctor writes you a prescription and recommends several types of contact lenses based on your lifestyle and needs.
During the examination, parameters such as visual acuity in each eye, refraction, the state of accommodation and the fundus, the thickness and shape of the cornea, and so on are determined. Not only the quality of the patient's vision depends on the accuracy of all data, but also how comfortable it will be for you to use certain types of contact lenses. For ophthalmoscopy (examination of the fundus) and measurement of the radius of curvature, for example, it is important to have the necessary equipment that allowsdo full research. So in order to feel comfortable using contact lenses and they do not cause any irritation, a visit to the doctor is a must.
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 be left on at night and do not require special care. And people who spend a lot of time in front of a computer monitor need those that have increased gas permeability. Such a lens does not dry out the mucous membrane of the eye and prevents possible irritation.
Finally, the doctor offers some kind of contact lenses, depending on all the above parameters and the patient's financial capabilities, and also teaches how to use and gives recommendations on how to care for them.
With the correct selection of contact lenses, it is necessary to visit a doctor from time to time. Perhaps some of your settings have changed and you will need to change the recipe.
Recommendations for care and use
- Wash hands with soap and water before putting on and taking off lenses.
- Makeup is applied after the lenses are put on.
- Always use a new solution and keep an eye on its expiration date.
- The container is replaced every three months.
- Each time contact lenses are removed, they must be gently cleaned under running water or solution.
- Use special tweezers. He is notdamages lenses.
- If contact lenses are damaged, they need to be replaced.
- You cannot store two lenses in one container cell.
- It is not recommended to swim with lenses as they can be washed away by water.
- The solution is poured into the container, and then the lenses are placed in it.
- Contact lenses left without solution dry out quickly and deform.
If you follow the above and other recommendations prescribed by your eye doctor, then the use of contact lenses in everyday life will be comfortable and will not cause harm.
