Individual production of contact lenses. Manufacturing of contact lenses: technology, methods
ZhGKL are manufactured strictly according to individual order, taking into account all the patient’s parameters, as they require a more accurate match of the inner surface of the lens to the surface of the cornea.
Wholesale price from 2500 rub.
ALWAYS MADE TO CUSTOM ORDER
no prepayment - for regular customers
30% prepayment - for new clients (Moscow, Kaluga, Obninsk + all other regions of Russia)
full prepayment - for residents of other countries
REGULAR PRODUCTION (GROUP): lenses are sent for production upon placing an order (from 30 lenses), without additional extra charge.
Order formation usually takes from 3 weeks to 2 months (check the stage with the operator). The lenses are then manufactured within approximately 2-3 weeks + delivery from the manufacturer takes 3-10 days. That is, the order arrives approximately 1-3 months after placement.
URGENT PRODUCTION (INDIVIDUALIZED) : Your order is sent for production individually, right on the day of registration, without any expectations, and also arrives individually, without waiting for other orders. That is, the order arrives approximately 2-4 weeks after placing.
When ordering by large wholesale for free
When ordering by average wholesale + 600 rubles
When ordering in small wholesale + 999 rubles
When ordering retail + 1500 RUR
Material: F2 produced by CONTAMAC
Manufacturing method: turning
Packing: bottle with 1 piece
Rigid lenses for astigmatism correction:
-inner radius from 7.9 to 9.0, step 0.05
-toricity T3-T12
-eccentricity from 0.2 to 1.2, step 0.1
Rigid lenses for keratoconus correction:
-internal radius from 4.8 to 7.2, step 0.05
- internal optical zone diameter from 5.5 to 6.5, step 0.1
-eccentricity from 1.0 to 2.8, step 0.2
To place an order for rigid gas permeable lenses, you must indicate in " Additional information"lens diameter (mm), inner diameter of the optical zone (mm), number of internal radii (chamfers), including the optical zone, size of each radius (mm), width of each radius (mm), feed amount for each radius (mm), refraction lenses (dopters).
For example, the lens diameter is 9.6 mm, the internal diameter of the optical zone is 7.3 mm, the number of internal radii is 4, refraction is -6.5 diopters,
size of each radius, width of each radius, feed
8,69 0,45 0,000
8,11 0,35 0,680
7,82 0,35 1,016
7,60 7,30 1,260
For keratoconus, you need to indicate in the "Additional Information" the diameter of the lens (mm), the internal diameter of the optical zone (mm), the number of internal radii (chamfers), including the optical zone, the size of each radius (mm), the width of each radius (mm), the size feed for each radius (mm), lens refraction (dopter).
For example, the lens diameter is 9.5 mm, the internal diameter of the optical zone is 6.0 mm, the number of internal radii is 8, refraction is -10.5 diopters,
size of each radius, width of each radius, feed
9,50 0,156 0,000
8,50 0,241 1,155
7,50 0,244 2,337
7,20 0,282 2,695
7,00 0,231 2,930
6,80 0,248 3,162
6,30 0,240 3,738
If necessary, a copy of the certificate is issued along with the order.
These lenses can be purchased at wholesale prices!
3250 rubles for 1 lens when ordering Concor products for an amount over 5,000 rubles at small wholesale prices (small wholesale)
2900 rubles for 1 lens when ordering Concor products for an amount over 10,000 rubles at average wholesale prices (average wholesale)
Contact lenses have long established themselves as a reliable method of vision correction. They are extremely relevant in case of myopia. farsightedness or astigmatism. Due to the fact that the latest materials and technologies are used in their production, they are a worthy replacement for glasses. We will talk further about the features of different types of lenses, their characteristics and disadvantages.
Features of the selection of contact lenses
When selecting, you need to take into account various criteria, especially taking into account optical power, radius of curvature and, of course, the material from which they are made. The right choice allows you to find good sharpness vision and feel comfortable during use. Undoubtedly, the quality of vision that is provided by contact lenses is much higher than the quality that a person receives by wearing glasses. This is explained by the fact that lenses are capable of forming a harmonious system with the surface of the eye. Moreover, there are no restrictions on the field of view or the possibility of damage due to bad weather conditions.
Lenses have become popular because they are not only easy to use, but also relatively low cost and, most importantly, they can protect the eyes from operations to restore vision. All surgical interventions create the possibility of complications, so it is better not to risk your eye health.
Those people whose occupation is different from their usual cannot do without contact lenses. Agree, it is unlikely that an athlete, race car driver or diver will find time to care for his glasses. By the way, lenses are great option for people who have different visual acuity in the left and right eyes. The modern range of such devices is represented by a wide optical range and different types: toric, aspherical, multifocal, as well as colored lenses of various shades.
Classification of modern contact lenses
Today, contact lenses can be divided into subgroups based on several parameters.
So, based on the time criterion, they distinguish:
According to the nature of wearing they are distinguished:
They can also have a special design and all kinds of colors:
Depending on what material served as the basis for manufacturing, there are soft and hard contact lenses, which we will talk about in more detail.
Benefits of soft contact lenses
Such devices are used by almost all people today. Doctors warn that you should not violate the prescribed regimen; you must take them off at night. Of course, it is much more convenient to wear lenses without removing them, but such an action can provoke swelling of the cornea. This condition can occur due to the fact that the cornea does not receive sufficient oxygen supply, and this, in turn, is fraught with very serious consequences.
The structure of the cornea of the human eye is specific, since it is devoid of blood vessels, so it is forced to receive oxygen and elements for nutrition from the air environment, as well as from tear fluid. Moreover, when the cornea is covered with a contact lens, then it is completely deprived of oxygen and other nutrients. Sometimes attempts to compensate for the lack of oxygen provoke the formation of new vessels, which over time grow into the corneal tissue. This process may result in a deterioration in visibility transparency and the creation of visual interference, which together leads to sharp decline vision. But soft lenses capable of preventing the possibility oxygen starvation cornea and solve the problem of vision correction.
Soft lenses can be made from a hydrogel polymer. Such material has already proven good compatibility with ocular tissues, but sometimes it can cause ocular hypoxia, that is, lack of air. After the implants are installed, air is delivered to the cornea using water contained in the lens. That is, than more water is in the optics, the more oxygen it can receive. But water tends to evaporate quickly. A person will immediately feel discomfort when wearing it, which indicates that the lens has dried out. When its water content exceeds the norm, it will no longer be able to retain its shape well.
Maximum possible ability oxygen transmission in hydrogel lenses is no more than forty conventional units. But ophthalmologists claim that to prevent chronic hypoxia, the cornea must receive more intense doses of oxygen, which amount to a coefficient of eighty units or more.
Soft models can also be made from silicone hydrogel. Thanks to the two components of the lens, it is ideally compatible with the eye tissue and, most importantly, does not interfere with the normal supply of oxygen to the cornea. Silicone is such a versatile material that it can easily provide high oxygen throughput up to one hundred and fifty conventional units. This fact completely eliminates the possibility of insufficient nutrition of the cornea. The hydrogel also helps to moisturize the cornea and make the lenses comfortable to use.
Lenses of this type contain less water, so evaporation of liquid is not a problem for them. Their worthy prerogative is the ability to use for a long time, without feelings of discomfort or excessive dryness. This can be explained by the fact that in finished goods the manufacturer introduces special additives for moisturizing. In addition, the optical mirror passes strict methods processing using plasma materials. Such properties of these contact lenses make it possible to use them without interruption during sleep.
Due to their high density, soft lenses are easier to put on and take off, because they can keep their shape perfectly for a long time. The next advantage is also that lipid and protein deposits do not appear in them over time, and this, in turn, extends their comfortable use.
Your ophthalmologist can offer you two types of silicone hydrogel contact lenses. The first ones can be safely worn for a week in a row (without being distracted by nighttime removal), and the especially durable ones allow you to use them for a month. They are perfect for those people who work long time in a non-interruption mode, for example on duty or in a security environment.
Modern silicone hydrogel lenses help correct not only the manifestations of myopia or farsightedness. but even forget about astigmatism.
Features of hard contact lenses
Innovative models have such an important characteristic as gas permeability. This contributes to the normal ability of the cornea to receive air and nutrients from the environment. Like soft options, hard lenses have silicone as their main component. This material was not chosen by chance, because, despite its strength, it does not protect the surface of the cornea from air supply. Some lens designs may exceed the gas permeability characteristics of soft material counterparts. Although soft silicone options boast a high degree of breathability, they are still inferior to hard silicone models. No matter how paradoxical it may sound, hard gas-permeable contact lenses have a more gentle effect on eye health than soft counterparts.
In addition, with hard contact many lenses are connected positive points, such as:
Of course, hard lenses cannot be ideal in use, as they have several negative aspects. As a rule, patients need some time to adapt and this period lasts on average at least a week. But after this, patients noted the disappearance discomfort if there was no break in wearing lenses for a couple of days. In this case, you need to be prepared to get used to the lenses again.
Some people have noted that after they used hard lenses, their correction with glasses stopped working. That is, when using glasses, vision did not improve, it remained at the same level, and the image was devoid of clarity. This often happens because hard lenses can actually change the shape of the cornea. But if you take breaks for a while, the shape of the cornea and visual acuity are gradually restored. Therefore, there is no need to rush and give up using hard lenses prematurely.
In truth, the process of fitting lenses based on hard silicone is complex, because the doctor must ensure the ideal ratio of the hard lens to the surface of the cornea.
Contact lenses are an excellent option not only for correction, but also for preserving vision for a person of any age. The most important step on the way to good vision is to choose the most acceptable option. To do this, you will need to undergo a qualified examination by an ophthalmologist, as well as follow all his recommendations and prescriptions. In no case should you violate the wearing regime of lenses, regardless of their type.
Rigid gas permeable contact lenses: reviews, manufacturing. Hard Contact Lens Care: Daily Cleaner for Hard Gas Permeable Contact Lenses
December 8, 2015
Today there are many ways to correct vision. Very often, contact lenses are used to improve its severity and eliminate other problems. Depending on the type of material, soft and hard gas permeable contact lenses are distinguished. Of course, the first type is most often used, however, the latter also have many advantages.
Materials for making hard lenses
Hard lenses became widespread at the end of the twentieth century. Then the main material for their manufacture was polymethyl methacrylate. The lens itself was relatively small in size. The disadvantage of such lenses was the lack of gas exchange. Access of oxygen to the cornea was achieved only due to the mobility and small size of such a correction device. However, today more modern and high-quality materials are used. Rigid gas permeable contact lenses are made from fluoro-silicone compounds. Thanks to this, the lenses have good oxygen permeability. It is worth noting that they are quite comfortable, they are made individually, and an exact fit is made for a specific patient.
Indications for the use of hard lenses
Soft contact lenses have limitations in their optical power range. They are often prescribed for myopia up to -12 diopters, myopia no higher than 8 diopters. A more severe degree of myopia requires specific correction. Soft lenses with high optical powers will have considerable thickness in this case. This, in turn, increases the risk of complications (tight fit can lead to eye hypoxia). You can, of course, use glasses, but today experts offer modern rigid gas-permeable contact lenses. They have wide range refraction - from -25 diopters to +25 units. Usage modern material ensures sufficient oxygen supply to the eye. Moreover, the thickness of such lenses is not much different from the corresponding parameters of soft products for vision correction. 
Hard Lens Design
Modern hard lenses have an optical zone that is located in the center of the product. Its diameter does not exceed 8 mm. Thanks to the sliding zone, which has a specific structure, the lens is securely fixed on the eyeball. The marginal region has the smallest dimensions. It is she who is responsible for comfortable wearing of the product, provides normal exchange tear fluid under the lens.
The main advantages of these lenses
Many patients note that rigid gas-permeable rigid lenses are less susceptible to deformation and creasing. Due to the fact that their diameter is slightly smaller than that of soft lenses, such products leave the peripheral zone of the cornea open. This, in turn, does not disrupt the tear exchange process. They are also more resistant to protein deposits, so the period of safe operation increases. Since the composition is completely free of water, hard lenses cannot dry out, the patient does not need to use special moisturizing drops. It is important to note their cost-effectiveness: the indication for replacement is only a change in visual acuity. Rigid contact lenses are also indicated for astigmatism. Reviews from patients indicate that correction with soft lenses in this case is quite difficult; the only option is to use hard products. Orthokeratological correction is also widespread. She assumes use of hard lenses only at night. 
Orthokeratology. What is the essence of the technique
This type of vision correction allows you to maintain visual acuity during the daytime, but at night you need to wear special lenses. During sleep, the cornea of the eye changes; its optical zone becomes flatter. This form lasts the entire next day. As a rule, the effect of such a correction can last two days. Night lenses are good for children, patients with a progressive form of myopia, if there are contraindications for surgery to restore vision. Also, this method is often chosen by people of certain professions: athletes, military personnel, builders, etc. Contraindications to orthokeratology therapy are diseases of the cornea, eyelids, all kinds of inflammatory processes, and dry eye syndrome. 
Disadvantages of using hard lenses
In addition to the above advantages, hard lenses also have their disadvantages. First of all, a certain period of adaptation is required (about a week). After getting used to it, the discomfort disappears, but even a short break in wearing requires new getting used to the products. Some degree of corneal deformation is observed if rigid gas permeable contact lenses have been used. Reviews from patients indicate that using glasses after such lenses does not bring the desired result: the image becomes blurry and the sharpness decreases. However, this is a temporary effect. After the cornea has been restored, you can safely use glasses without losing the quality of your vision. Also, the process of selecting products is quite lengthy; their initial cost will also be an order of magnitude higher than that of soft lenses. 
How to choose the right gas permeable lenses
In order to choose hard lenses wisely, you first need to consult a specialist. It determines visual acuity and the maximum degree of correction. Using special equipment, the ophthalmologist measures the necessary parameters of the patient’s cornea. What follows is trying on several pairs. All these manipulations are necessary for perfect lens fit. Manufacturing hard contact The fitting of lenses is carried out purely individually, and more than 20 parameters of the eye are taken into account. The engineer models the required design (optical zone, sliding zone, edge region). Next, the product is turned on a special machine in full accordance with the layout. Most famous manufacturer in this area - the German company Wohlk. This manufacturer ensures high quality products. As a rule, after 14 days you can receive a ready-made set of lenses. 
Daily care of hard contact lenses
First of all, any lenses require proper personal hygiene. Hands should be washed with soap and water before removing or putting on. It is best to wipe them with a waffle towel to avoid getting various lint on the lens. Storage containers must be kept clean. For women there are special rules. Makeup should only be applied after the lens is in place. Accordingly, remove it after removing the product from the eye. A daily cleaner for hard gas permeable contact lenses is also necessary. With its help, impurities and tear fluid are removed. A deeper cleaning is carried out once a week. It is worth noting that you cannot rub the lenses too much, so as not to disturb the optical properties. Today, a multifunctional cleaner for hard contact lenses is widely used. It allows you to effectively remove protein deposits (for example, Boston Simplus solution) and does not require additional enzymatic purification. It also perfectly disinfects and softens contact lenses. Over time, the product becomes more difficult to clean. In this case, hard lenses can be polished in a special laboratory. 
Special requirements for owners of hard lenses
Wearing hard lenses imposes certain responsibilities on the patient. Visits to the ophthalmologist should be regular. This will enable the specialist to assess the condition of the eyes. If there is the slightest change in the condition of the eyes, you should consult a specialist. Timely treatment will help avoid conditions such as corneal edema, microbial keratitis, conjunctivitis, corneal ulcers, and allergic reactions. Rigid gas permeable contact lenses are an excellent solution for vision correction in many cases, but they require proper and careful care.
Hard contact lenses
Yashina Olga Nikolaevna
Candidate medical sciences, Head of the Department of Refractive Pathology
In the world of contact correction, the leader is, of course, occupied by soft contact lenses.
In the minds of the average person, hard lenses are associated with the very first contact lenses, which were made first from glass, then from polymethyl methacrylate (PMMA). These lenses were very uncomfortable to wear, did not allow oxygen to pass through at all, they had to be boiled, special cleaners used, etc.
Today, rigid lenses generally refer to gas permeable contact lenses (GP lenses).
What are the features of hard lenses?
If the contact lens has low gas permeability, then the cornea under it “does not breathe.”
Modern rigid gas permeable lenses are made from silicone-based materials. As you know, one of the most important characteristics of any contact lenses is the oxygen transmittance coefficient (Dk/t).
The cornea receives oxygen from the surrounding air, and if the contact lens has low gas permeability, then the cornea “does not breathe” and develops chronic hypoxia, corneal edema, vascular ingrowth - all this leads to a decrease in the transparency of the cornea and long term to irreversible visual impairment.
Silicone has high gas permeability - many times higher than soft contact lenses. Silicone hydrogel contact lenses have a fairly high oxygen transmittance, but still this indicator inferior to hard silicone-based lenses.
Providing a high supply of oxygen, rigid gas permeable lenses have minimal impact on the physiology of the cornea and are the safest for the health of your eyes.
Benefits of rigid gas permeable lenses
In addition to high oxygen transmission, rigid gas permeable contact lenses have other positive properties:
Most importantly, rigid gas permeable lenses can provide better visual acuity in some cases compared to soft contact lenses:
Disadvantages of hard lenses
It will take you some time to get used to wearing hard contact lenses.
Hard contact lenses are naturally inferior to soft lenses in terms of wearing comfort. It will take you some time to get used to them. Adaptation can reach 5-7 days, then most users stop feeling any discomfort, but if you take a break from wearing them for at least a few days, you will have to get used to hard lenses again.
In some patients, after wearing hard lenses, spectacle correction no longer works, i.e. If such patients remove their lenses and put on glasses, their vision is poor and the image is blurry.
This is due to the fact that hard lenses slightly change the shape of the cornea (the same principle, only to a greater extent, underlies orthokeratology). Gradually, the cornea returns to its shape and vision with glasses is restored, but many users stop wearing hard lenses as a result.
The selection of rigid gas permeable lenses is more complex compared to soft contact lenses, since a rigid lens must perfectly fit the surface of the cornea, accordingly, the time required to select lenses will be longer and the cost will be higher.
Technologies for the production of rigid gas permeable lenses are constantly evolving. Manufacturers strive to create lenses that are as comfortable as soft contact lenses. But today, many users primarily choose the safety and health of their eyes, giving preference to gas permeable lenses.
Hard contact lenses
Hard contact lenses are often perceived as outdated, uncomfortable optics made of glass and polymethyl methacrylate. Such samples previously did not allow oxygen to pass through and required boiling and the use of purifiers. Modern LCDs are gas permeable. The site obaglaza.ru will introduce you to the positive qualities of this “solid” optics.
Features of LCD
The Dk/t coefficient, which characterizes oxygen permeability, is important for any contact lenses. The cornea of the eye will not receive oxygen from the atmosphere and will not breathe if the optics material has low gas permeability. Consequences &minus swelling, hypoxia, vascular ingrowth. Vision is irreversibly deteriorated due to decreased transparency of the cornea.
Today, rigid gas permeable lenses are made from silicone-based raw materials. Their Dk/t value exceeds that of soft contact lenses (even silicone hydrogel). Therefore, GCLs have minimal impact on the cornea. The gentle effect on the eyes has a positive effect on their health.
Advantages and disadvantages of hard GP lenses
Advantages
- Thanks to high density Made from the original material, hard contact lenses retain their shape and wrinkle little when blinking, ensuring image stability.
- It attracts users, especially older ones, because it is easy to use. LCD cannot be accidentally torn, but can be broken purely theoretically.
- Protein deposits get onto the optics from the tear fluid. The resistance of the surface of hard lenses to them increases comfort and prolongs the period of safe wearing.
- The peripheral extreme zone of the cornea is accessible to oxygen, since its diameter is slightly larger than the diameter of the GCL. The tear washes away dead cells and foreign particles without interference.
- In the composition of the material manufacturing hard There is no water in GP contact lenses. In unfavorable conditions (strong wind, heat) they do not dry. There is no need to use moisturizing drops.
- Economic benefit: the duration of use is unlimited, with the exception of changes in the patient's vision. Obaglaza.ru specialists advise only to properly care for your optics.
Rigid gas permeable lenses sometimes provide vision best quality. Cases when correction using LCD is preferable:
Flaws
You need to get used to wearing hard lenses; they are not as comfortable as soft ones. Adaptation occurs within a week, the main thing is not to interrupt wearing, otherwise you will have to adapt again.
Some patients who wore GCLs experience a decrease in vision with glasses and the cessation of the effect of spectacle correction. Hard lenses act on the cornea, changing its shape. However, it is gradually restored with a pause in the use of liquid crystal lenses, and visual acuity returns when wearing glasses. Obaglaza.ru recommends taking this nuance into account and not rushing to categorically exclude the use of such contact lenses.
It is difficult to choose rigid GP lenses - the optics must ideally fit into the surface of the cornea. This also determines the high cost of housing and communal services.
Selection of hard contact lenses
Continuous improvement of production technologies is a priority for manufacturers of rigid gas permeable lenses. Hard optics are constantly approaching soft optics in terms of comfort, which encourages users to prefer safe hard GP lenses.
Great quantity medical centers with detailed eye examination services, diagnostics, selection of optics suitable for a particular patient. Choice necessary treatment You should trust only professional ophthalmologists, experts at obaglaza.ru are confident. Never neglect a comprehensive eye examination.
Johnson & Johnson was founded in 1886. It is one of the largest American manufacturers of cosmetic and medicinal products, as well as contact lenses. Johnson & Johnson products are known throughout the world and are sold in many countries.
In 1987, Johnson & Johnson introduced innovative contact Acuvue lenses, intended for a seven-day wearing period. Since that time, over 2 billion contact lenses have already been produced. Regarding the lenses supplied on Russian market, then most of them are produced in Ireland at the famous Limerick plant.
Popular brands : 1-Day Acuvue TruEye, Acuvue Oasys, 1-Day Acuvue Moist, 1-Day Acuvue Define, Acuvue Oasys 1-Day.
CooperVision
CooperVision is an American manufacturer of contact lenses. The company was founded in 1958. The main factories for the production of contact lenses of Cooper Vision are located in the English city of Hampshire, as well as in the American cities of Rochester and Huntington Beach.
The company's headquarters are based in Irvine, California.
The US facilities primarily manufacture soft toric and spherical contact lenses, while the UK manufactures elective soft contact lenses.
It was the specialists from Cooper Vision who first developed soft contact lenses for regular replacement. The basis of these lenses is the innovative material tetrafilcon.
Popular brands : Proclear, Biofinity, Avaira, Myday, Biomedics 55.
Alcon
Alcon is a recognized world leader in the manufacture and sale of ophthalmic products. The company's headquarters is located in Texas. More than 2,500 employees work for the benefit of Alcon.
The company was originally founded in Fort Worth in 1947 (Texas). At the origins of the company were two American pharmacists - Robert Alexander and William Conner. It was the first syllables of their surnames that served as the basis for creating the name of the company.
In 1977, Nestlé acquired Alcon, as a result of which the sales area of this company's ophthalmic products was expanded. This is how the manufacturer entered the European market. Currently, Alcon factories are located in Spain, Belgium, Mexico, France and Brazil.
Subsequently, Alcon also began to develop and establish production of surgical equipment for ophthalmology.
Bausch & Lomb
Bausch & Lomb is a leader in the manufacture and sale of contact lenses.
The company was founded in America in 1853. The founders of the company were emigrants from Germany J. Bausch and H. Lomb. They chose to specialize in the production of special and high-precision optics: telescopes, microscopes, binoculars, night vision devices. In 1971, Bausch & Lomb was the first company to receive FDA approval to market soft contact lenses.
Bausch & Lomb manufactures a wide range of ophthalmic products and surgical equipment, which were previously produced under the Chiron and Stortz brands.
Bausch & Lomb has sales centers and factories in 25 countries.
Popular brands : PureVision 2, Biotrue ONEday, Soflens Daily Disposable, Optima FW.
Korean companies
In the last few years, several Korean companies have appeared on the contact correction market, such as OKVision, G&G Contact Lens. The most popular among their products are colored contact lenses due to their bright colors and affordable prices.
Contact lenses are small clear lenses that are placed directly on the iris of the eye. The main purpose of such lenses is to correct refractive errors (increase visual acuity). The exception is decorative and cosmetic contact lenses, which are mainly used as decoration, although they often perform a double function - vision correction and eye decoration.
According to statistics, at least 125 million people use contact lenses, which is approximately 2% of the entire population. More than 40% of contact lens users are young people aged 12-25 years.
People use contact lenses for optical or functional reasons. Lenses, compared to glasses, generally provide better peripheral vision and do not fog up in extreme weather (rain, snow, humidity). This makes them more suitable for outdoor use, especially when active activities sports. There are also a number ophthalmological diseases(for example, aniseikoria, etc.) the correction of which is more effective when wearing contact lenses rather than glasses.
The main optical difference between contact lenses and glasses is the absence of distance between the eye and the optical glass, which ensures distortion - the visibility of objects without distortion.
A little history
Incredibly, the first idea to use contact correction came to Leonardo da Vinci back in 1508. While sorting through the archive of his works, scientists came across drawings of a ball filled with water, through which a person with poor vision could look at surrounding objects. In addition, his notes revealed diagrams of lenses that can easily be called a prototype of modern ones.
In 1637, the work of Rene Descartes was published, with drawings of an optical device. The device was a glass tube filled with water, a magnifying glass was attached to the end of which, and the other end was placed against the eye. This device was subsequently modified by the English physicist Thomas Young, who used a shorter tube, thereby compensating for the shortcomings of refraction.
The German physiologist Adolf Fick described a glass lens with optical power in 1888. And made optical lens and introduced its application into medical practice ophthalmologist August Müller in 1889. His lens became a new correction method and the topic of his doctoral dissertation.
Until the second half of the last century, the material used for making contact lenses was organic glass (PMMA). These lenses were hard and uncomfortable to wear, causing the sensation of a foreign body in the eye. In addition, they absolutely did not allow oxygen to reach the cornea, which is necessary for its normal functioning. In 1960, the Czech scientist Otto Wichterle synthesized new look polymer (HEMA) from which soft contact lenses were first made. HEMA polymer had the ability to absorb water (up to 38%), after which it became elastic and soft. Not more than 10 years ago, a new generation of contact lenses was created - silicone hydrogel. These soft lenses provide even greater comfort and absolute safety when worn.
Today, I use a lot of classifications for contact lenses: according to the material of manufacture, according to the frequency of replacement (the period after which the lenses are replaced with new ones), according to the mode of wearing them (daytime, extended, continuous, etc.), according to design (spherical, toric, multifocal ), according to the degree of transparency/color (transparent, colored, decorative). But they are all divided into two main groups: soft lenses and hard ones.
Soft contact lenses are preferred by up to 90% of all contact lens users. In turn, such contact lenses are divided into hydrogel and silicone hydrogel.
Hard contact lenses are usually used for correction complex cases vision pathologies (for example, with high degrees of astigmatism and keratoconus), in addition, only they are used in orthokeratology - a relatively new direction of ophthalmology. The new generation of hard lenses not only perfectly holds their shape, which makes them more convenient to use, but also provide a high degree of oxygen transmission to the cornea. These lenses are called rigid gas permeable contact lenses.
Colored contact lenses are designed to radically change the color of the iris, while tinted contact lenses are designed to enhance or change the shade of the existing color. Such lenses can be made with diopters, in which case, in addition to changing eye color, they will improve vision. But in most cases, such lenses are produced “zero” - without diopters and are necessary only for a cosmetic effect.
On the color perception of visible objects, colored and tint lenses do not affect, since they are transparent in the center. True, such lenses are not recommended for use in low light conditions (in twilight and darkness), because the human pupil dilates when there is insufficient lighting and then the colored part of the lens will fall into the visibility zone, which will cause vision difficulties. Such lenses should not be worn while driving or engaging in activities requiring high attention.
Designation of contact lens parameters
All contact lenses have the following characteristics (parameters), which must be indicated on the sales packaging:
- Material of manufacture.
- Lens diameter (D, BCR).
- Radius of curvature (ВС, ВСR).
- Optical power of the lens.
- Thickness of the center of the lens.
- Cylinder axes.
- Construction (design).
- Optimal wearing mode.
- Replacement frequency.
Long-term wear lenses (6-12 months) are usually packaged in special bottles. For lenses that need to be replaced more frequently, blisters are used as packaging.
Wearing mode - the period of time that lenses can safely remain on the eyes:
- Daytime (put on in the morning, remove before going to bed at night).
- Long-lasting (worn for 7 days, not removed at night).
- Flexible (worn for 1-2 days, not removed at night).
- Continuous (worn continuously for up to 30 days, do not remove at night). A similar regime is possible for some types of silicone hydrogel lenses and requires consultation with an ophthalmologist.
Nightwear (should be put on before bed and taken off in the morning). Orthokeratological lenses after which the patient sees perfectly all day without additional funds corrections.
Design (construction) of contact lenses
- Spherical. Their purpose is to correct myopia and hypermetropia.
- Toric - for the correction of myopia and hypermetropia with accompanying astigmatism.
- Multifocal - for the correction of presbyopia.
Improving the quality of vision in any type of lens is achieved by their aspherical design. Various polymers are used in the manufacture of contact lenses. The main part consists of hydrogel and silicone hydrogel materials, of which there are about 10 types.
The properties of a contact lens are mainly determined by the material it is made of. The main characteristics of contact lens material are considered to be: its water content and oxygen permeability.
- Low water content (<50%).
- Average water content (50%).
- High water content (>50%).
The more water a hydrogel lens contains, the more oxygen the cornea will receive, which has a positive effect on eye health. But increasing the percentage of water in the lens makes it softer, which makes it more difficult to handle. Therefore, the water content in hydrogel lenses usually does not exceed 70%.
The main indicator for silicone hydrogel lenses is the oxygen transmission coefficient (Dk/t), which is in no way related to the water content. In this case:
- Dk is the oxygen permeability for the lens material.
- t is the thickness at the center of the lens.
The Dk/t indicator for hydrogel lenses is usually in the range of 20-30 units. For daytime wear, this is enough, but to keep the lenses on your eyes at night, much higher values are needed. Silicone hydrogel lenses have a Dk/t value of approximately 70-170 units.
The diameter of the contact lens and its radius of curvature affect how the lens “sits” in the eye. As a rule, lenses are produced with one or two radii of curvature. If a contact lens does not fit well due to a discrepancy between the radius of its curvature and the shape of the cornea, serious discomfort occurs, which can lead to refusal to wear lenses.
The main optical indicators of a contact lens are: sphere power (with a plus or minus sign, in diopters), cylinder power (indicated in diopters), localization of the cylinder axis (indicated in degrees). The last two parameters are necessary only for toric lenses that correct astigmatism.
The contact lens performance parameters for one and the other eye of a patient may be different.
Terms of use
If contact lenses are incorrectly selected and fitted incorrectly, interference and discomfort will inevitably occur. To eliminate it, you should contact an ophthalmologist. If the radius of curvature of the lens is larger than necessary, they seem to “float” in the eye, and if it is smaller, on the contrary, they “get stuck” and this part of the cornea is no longer supplied with oxygen. In both cases, such lenses should be replaced with lenses with the desired radius of curvature. Properly selected lenses are characterized by slight movement when blinking (a fit without rigid fixation), but most of the time they are in a central place. At long-term wearing lenses with a smaller radius of curvature often cause corneal hypoxia without oxygen, which increases the risk of infectious processes, since when sufficient quantity Infectious agents cannot survive in oxygen.
You can swim in lenses only if you use special sealed goggles or a swimming mask. You cannot wear lenses to the sauna or bathhouse. If unboiled water gets on them (shower, swimming pool), they need to be replaced with fresh pair. Contact lenses are designed to be worn at any ambient temperature, including extreme heat and cold.
Contact lens wearers are required to undergo annual eye examinations with an ophthalmologist.
Possible complications
There are some complications associated with contact lens use, including:
- Infectious diseases (keratoconjunctivitis sicca, etc.).
- Allergic reactions.
- Hypoxia reactions with oxygen deficiency for the cornea.
- Mechanical damage cornea.
Neglecting the rules of hygiene or care of lenses (it is necessary to treat them with a special cleaning solution), infection of the mucous membrane may occur. Violation of the terms of wearing lenses for planned replacement or wearing lenses with low rate oxygen permeability, possible growth of blood vessels into the cornea of the eye (neovascularization) and other complications, often irreversible. They become a contraindication to further use of contact lenses.
Manufacturing of contact lenses
The production of contact lenses is carried out in several ways: centrifugal molding, casting, turning. There are also methods that combine all of the above techniques.
- Turning. With it, “dry” polymerized workpieces are processed on a lathe. Lenses with complex geometries are produced through the use of computer control programs. After grinding, the lenses are polished and saturated with water (hydrated) to the required parameters, then they undergo chemical cleaning. The final stage production includes lens tinting, sterilization, inspection, packaging and labeling.
- Casting. This is a less labor-intensive method than turning. First, a special metal matrix mold is made for the lens. Then plastic copy molds are cast using a matrix and liquid polymer is poured into them, which hardens under the influence of ultraviolet light. The finished lenses are polished, hydrated, tinted, sterilized and packaged.
- Centrifugal molding is the oldest method of producing contact lenses. In this case, a liquid polymer is injected into a mold rotating at a certain speed and exposed to high temperature and/or UV radiation, which is necessary for its hardening. Then the workpiece is removed from the mold, saturated with water and subjected to processing identical to the turning method.
One example of a combined method for producing contact lenses is the reverse process. With it, the centrifugal molding method is used to obtain the front surface of the lens, and turning is carried out to obtain the rear surface.
The world's largest manufacturers of contact lenses are recognized as: Johnson & Johnson (Acuvue product), Neo Vision, Bausch & Lomb, etc.
You can find out more about individual types of contact lenses in the relevant sections:
For the manufacture of contact lenses latest generation Highly sensitive soft materials that are particularly smooth are used. In order to facilitate manipulations with such lenses, maintaining the integrity and sterility of the contact surface, special tweezers are produced. They are used to remove lenses from the container; tweezers help when removing contact lenses and immersing them in a solution poured into the container’s tray, as well as during the process of rinsing them with special disinfectants.
Everyone who uses contact lenses knows about the need to keep them perfectly clean, because the health of their own eyes and the quality of vision depend on this. In this regard, to avoid infection eye infections, at the same time as purchasing a new pair of lenses, it is worth buying a container for storing them, as well as a special solution that in the best possible way Suitable for both the eyes themselves and the optics.
New contact lenses from Baush + Lomb, called SofLens Daily Disposable, are affordable option daily lenses. They do not require daily maintenance and provide clear vision at any time and in any lighting thanks to improved optics.
Adria Color colored contact lenses from the Korean company Interojo are in great demand and are extremely popular. These are lenses that allow you to correct various degrees of myopia and, as well as change tone, color and even appearance the eye completely. In the production of colored lenses, innovative coloring technology is used. Thanks to it, the dye is, as it were, locked inside the lens material, which increases resistance to fading and makes wearing products of this brand absolutely safe.
Daily contact lenses are shining example convenience, comfort and safety. Another name for them is “daily replacement lenses”, because they are designed to make your eyes rested and bright every new day. What distinguishes them from the already familiar scheduled replacement lenses is that every morning you need to open a new package, and every evening you need to dispose of lenses that have become unusable throughout the day. Actually, this is what silicone hydrogels do daily lenses so reliable and convenient.
We work with various types of hard contact lenses (Wohlk, Boston, Rose-K, SoClear, etc.).
Our specialists can select exactly those contact lenses that will provide the highest quality of vision in your case.
What are rigid gas permeable contact lenses?
It sounds kind of scary.
Soft contact lenses – the name is much more pleasant. However, you will be surprised that hard contact lenses allow oxygen to reach the cornea at a much faster rate. more than regular soft contact lenses and even the newest silicone hydrogel lenses, which are now the safest and most advanced soft contact lenses. And this indicator is almost the most important for those who constantly wear contact lenses.
Besides this hard contact lenses provide higher clarity of vision, are more resistant to deposits, and are much cheaper than soft contact lenses, since one pair of lenses is designed to be worn for up to 1-2 years.
Why then doesn't everyone wear hard contact lenses?
First - You will need adaptation, i.e. necessary certain time to get used to wearing hard contact lenses. This time is very individual from 3-4 days to 2-3 weeks. And it doesn't hurt.
Secondly, to successfully wear hard lenses you need to wear them every day(with a few exceptions), because if you don't wear them for a while, then you will need some time to adapt again
Hard contact lenses - an excellent option for those people who cannot achieve ideal vision with soft contact lenses. This is possible in several cases:
- those people who have higher demands on the quality of vision, for example shooters, operating surgeons, pilots, jewelers, etc.;
- those. who has astigmatism, especially of a high degree, and due to this, 100% vision is not achieved in soft contact lenses;
- patients with keratoconus ( irregular shape cornea);
- patients who need correction after previously performed surgical operations on the cornea ( laser operations to eliminate myopia, corneal transplantation, lens removal).
- patients who have problems wearing soft contact lenses (corneal vascularization, recurrent eye inflammation, excess accumulation sediments)
If you already use hard contact lenses and would like to purchase a new set, please note:
You can order or purchase hard lenses from us if the lenses were selected in our office. Hard lenses cannot be ordered in absentia, using a prescription for glasses/soft lenses or the parameters of old hard lenses. To purchase lenses in our office, you need to make an appointment, take a break from wearing your lenses for several days, and bring with you all the data that you have (from examination data to old glasses and contact lenses).
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