Tinted glasses lenses. Chameleon sunglasses for men and women

Photochromic lenses have become one of the main trends in modern Optics. Today, spectacle lenses with this technology provide many benefits to the spectacle wearer. Especially in combination with plastic (organic) high refractive index lenses.

These products can be found from many suppliers spectacle lenses. However, there are completely opposite opinions among Opticians and Clients regarding .

When we talk to a Client about photochromic lenses, every Optician is familiar with the question: “What happens if I drive into a tunnel?” The supposed “danger” in this issue was circulated in the press several decades ago, and is still fresh in the minds of many Consumers.

The answer to this question is very simple - due to the properties of car glass (windshield or side), glasses with photochromic lenses are unlikely to darken in the car. Of course, this does not apply when you are eating in a convertible. It is important to understand that photochromic lenses are not sunglasses.

A common, and certainly justified, objection from eyeglass lens manufacturers is that they do not want to combine everything specifications in one pair of glasses. Since the need for sunglasses and other special glasses, in addition to glasses, for constant wearing.

Thus, let's focus our attention on the individual assessment “for or against”. It goes without saying that thanks to intensive scientific research and developments, the number of “negative” features of photochromic lenses has decreased significantly.

transparent indoors quickly tinted sunscreens in the sun

The invention of the first photochromic lens took place more than 40 years ago. In 1964, we received the first report on a borosilicate lens doped with silver halide crystals. The name “photochromism,” by the way, is much older - already in 1899 it was used to describe changes in crystalline chemical compounds that reversibly change their color when exposed to light.

As is known, photochromic lenses darken when exposed to ultraviolet radiation(UV radiation). This is the main factor influencing the darkening reaction of the pigment molecules in the lens. However, this is not a “one-way street”, since the processes of darkening and brightening the lens occur in parallel.

The processes of darkening and clearing in photochromic lenses are influenced by many factors: temperature environment, sunny and geographical position. For example, known fact that sometimes photochromic lenses darken much more in cold and cloudy weather than on a warm and sunny day.

Today, almost all eyeglass wearers are aware of the dangers caused by ultraviolet rays (UV radiation). This provokes discussions about intellectual . Many opticians believe that changing light levels strain the eyes.

This process occurs in everyday situations, such as bright neon lights in a department store, bad light in the office at the computer, diffused light when driving in the rain or while spending time in the fresh air. Under these conditions, light-sensitive Clients complain of constant blinking, red eyes and headaches.

At the same time, people who wear photochromic lenses made of plastic have realized that the main application of this type of lenses is not in the extreme positions: “completely transparent” or “completely darkened”, but, above all, in large quantities variations between these positions.

It is for the universal convenience and ease of use in everyday situations that Clients love and purchase these lenses again. Photochromic lenses offer the glasses wearer excellent protection against and, not only in ideal conditions, but also with minute-by-minute changes in lighting conditions. So why not combine superior visual comfort with superior protection and clarity of vision?

At Premium Optics, calm, relaxed vision in lightweight, aesthetically pleasing lenses has become the standard. A good Optical Consultant will not offer his demanding Clients simple photochromic lenses with a standard refractive index of 1.50 (CR-39 material, for example), especially when the frame is “screwed” or “on a fishing line”.

If necessary, he will use photochromic lenses with a refractive index of 1.67, for example. These extremely thin and durable lenses not only provide excellent UV protection, they are also perfect for active outdoor activities. To create this lens, SEIKO uses a unique MR-10 material with “shockproof” features.

One more, additional opportunity, for Customers with high diopters, SEIKO launched the world’s thinnest plastic photochromic lenses with an ultra-thin refractive index n=1.74. Today, these photochromic lenses () set a new standard for aesthetics and lightness. They are suitable for creating fashionable, modern glasses, even with large prescription requirements.

This is why, in this situation, photochromic mineral lenses (glass) are at a disadvantage. In these lenses (with the exception of clear lenses), pigment molecules (halides) are distributed throughout the base material. It turns out that the photochromic reaction depends on the diopter of the lens. In a “minus” lens, the base of the material is thin in the center, and thickens towards the edges - accordingly, photochromic darkening is weaker in the center of the lens, relative to the edges. In a “plus” lens, it’s the other way around: the base of the material in the center is thicker, so the darkening in the center of the lens will be stronger than at the edges.

Photochromic plastic lenses do not immediately become photochromic while they are “half-finished”. Today, the most common photochromic technology is Transitions. It is offered by many major eyeglass lens suppliers.

For example, photochromatization of SEIKO SSV 1.67 Transitions spectacle lenses is the application of a mixture of a photochromic substance (group of molecules) to the front surface of a 1.67 “semi-blank”. Penetration into the lens material occurs approximately 0.15 mm inward, evenly distributed over the entire surface of the lens. The process is called “trans-boarding”. This allows the photochromic lens to darken up to 85% of the tint, regardless of diopter. detailed information Transitions technology is a mystery comparable to the Coca-Cola recipe.

Regarding the safety of driving a car, there are no restrictions: photochromic lenses are completely suitable for recognizing traffic lights and driving in the evening or at night.

The fundamental criterion for the quality of plastic photochromic lenses is the reaction speed, which currently reaches several seconds. Today, photochromic lenses in super-high (1.67) or ultra-high (1.74) refractive index achieve over 60% tint within 30 seconds at room temperature of 23 degrees.

Transitions photochromic lenses also lighten very quickly. In their lightest state, SEIKO Transitions photochromic lenses transmit almost 95% of the light entering them. That is, indoors, they are absolutely transparent. At the same time, they “cut off” harmful “UV radiation” with a wavelength of up to 395-400 nm - this is one of the highest levels of UV protection.

Today, mineral photochromic lenses (glass), which previously had the advantage of being scratch-resistant, are fading into the background. It's all about the development of high-tech "hard coatings" on plastic photochromic lenses that prevent damage from occurring. For example, all SEIKO Transitions lenses automatically have a double-sided coating that includes a clear optical varnish (HardCoat) that protects against minor damage and scratches.

Thus, photochromic plastic lenses with a maximum refractive index are suitable for absolutely everyone for daily use.

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Excessively bright sun can damage your eyes and discourage you from going outside in clear weather. If you have poor vision, it is inconvenient to wear sunglasses, and your wallet does not always allow you to have special tinted ones in addition to the regular ones. But even in this situation there is a way out - photochromic lenses, or so-called chameleon lenses.

Glasses with such lenses indoors are no different from ordinary ones. But as soon as their owner goes out into the light, the lenses themselves darken to the required level, protecting the eyes from exposure to ultraviolet rays. All this is thanks to special photochromic elements added at the manufacturing stage. They react to sunlight and darken, thereby protecting the user’s eyes.

When choosing photochromic lenses, you need to rely on several very important criteria:

1. Darkness level (minimum). It is important to pay attention to the minimum parameter, which shows how transparent the lens is in its normal state. The lower the value, the more transparent they are.
2. Darkness level (maximum). A parameter that shows how dark the lens can be in bright sunlight. The most great importance today – 90%. The higher the number, the darker and more expensive the glasses.
3. Speed ​​reaction. Old lenses took a very long time to darken and lightened for the same amount of time. Modern materials allow you to increase the speed of reaction of photochromes to sunlight.
4. Carrying in a car. If such glasses are needed for use in a car, then it is worth checking whether they will darken the interior (that is, whether they react to visible light).
5. Additional coverages. Most manufacturers make glasses using Transitions technology and add coatings themselves. These coatings can be different - dirt-repellent, ultra-durable, and so on. So you can choose according to your taste.

Not only the cost of one lens, but also the wearing comfort will depend on these parameters. At correct selection you will be able to find the perfect option. In our rating of the best photochromic lenses, we have selected the most successful options with reasonable prices. The models are selected according to the most advantageous characteristics and reviews from ophthalmologists. Remember: the price is for one piece, not a pair.

TOP 5 best photochromic lenses

5 Cantilen Clear Vision Photo 1.56

The cheapest photochromes
Country Russia
Average price: 1200 rub.
Rating (2019): 4.3

Russian single vision lenses in a spherical polymer design. They belong to the budget class of photochromic options and do not have the quality of more expensive analogues. However, the model is able to protect from sunlight at a decent level, so it copes with its main function. I'm glad that the manufacturer added an excellent Clear Vision coating, which has many functions. In addition to traditional strengthening and dirt-repellent properties, it also protects against electromagnetic waves. A special feature is a polarizing coating, so now there will be no unnecessary glare or double vision in the eyes.

There are not many diopters here - only from -8 to +6. There is no cylinder provided at all, so the model is not suitable for astigmatists. The lenses will be relatively thick at large diopters, since the refractive index is only 1.56. Available in two diameters - 65 and 70. You can choose from two standard colors - brown and gray. Interestingly, the dimming in calm state they do not - such photochromic lenses are perfectly transparent indoors. For the same reason, they are not suitable for drivers, although a polarized coating can improve driving comfort.

4 Rodenstock Perfalit 1.54 ColorMatic

The best ratio of price and quality
Country: Germany
Average price: 2950 rub.
Rating (2019): 4.4

Inexpensive but high-quality photochromic lenses from organic polymer. German quality pleased me here too. For a reasonable price you can get good lenses middle level. Capable of providing up to 85% dimming in bright light. Indoors, they do not become completely transparent - the residual effect retains approximately 8% darkness. The lens is not the thinnest, the refractive index is only 1.54. But the polymer material made it possible to make it thinner than plastic and, especially, glass analogues.

The diopter range is frankly small - only from -6 to +4. There are two diameters - 65 and 70 millimeters. Available in two standard colors – brown and grey. The lenses themselves are coated with one of two options: SPP or Duralux. The first is a nanotechnological coating with many functions, from brightening to dirt-repellent and strengthening. Duralux simply makes the surface more durable and resistant to physical damage. The good news is that the lens quickly reacts to changes in illumination - it takes several tens of seconds for it to change color.

3 HOYA DriveWear Hi-Vision Aqua 1.5

Best for drivers
Country: Japan
Average price: 10,000 rub.
Rating (2019): 4.5

Japanese quality especially for drivers. These photochromic polymer lenses were created for those who spend a lot of time behind the wheel. They have everything you might need on the road - high-quality polarizing coating and sensitive photochromic, capable of changing the degree of darkness in a matter of seconds. The color changes very softly from light yellow-green to rich brown, maximum darkening is up to 85% outdoors. In a car, the lenses will only be darkened by 50% to create comfortable conditions for driving.

The lens is single-focus; manufacturers provide diopters from -9 to +7.5, but, unfortunately, a cylinder is not provided. There is only one color, the signature green-brown. But there are three coating options - HVA (anti-reflective and dirt-resistant), SHV (durable and anti-reflective) and HVLL (a combination of the previous two with increased durability). All three options are slightly greenish (up to 25%) even in the absence of darkening factors. Taking into account the polymer material, the lens is of moderate thickness - refractive index 1.5. An important clarification: you can only use glasses during the day; they are not suitable for night driving.

2 Essilor 1.59 Airwear Transitions Signature 7 polycarbonate Crizal Alize + UV

Best for use on a computer. Wide range of diopters
Country: France
Average price: 6200 rub.
Rating (2019): 4.7

The manufacturer has tried to make really high-quality and universal photochromic lenses. And the French did it. This is a durable, thin and lightweight lens that can easily save your eyes from excessive ultraviolet radiation. It is made of impact-resistant polycarbonate treated with a special Crizal Alize+ UV coating. It gives the surface many useful characteristics - it is perfectly smooth and transparent, and is easy to clean from dirt. Important Feature– dust and dirt will not linger on the lens, so you will have to clean it less often.

This particular photochromic spherical model is single vision, you can purchase options from -12 to +7.75 diopters. In addition, it is easy to select the cylinder - from -6 to +5.75. The lens has a refractive index of 1.59 - it cannot be called the thinnest, but it looks quite aesthetically pleasing. The manufacturer provides two shades to choose from – gray and brown. In bright light they darken up to 88%. But in fact, the lenses will have a slight greenish tint even in poor light. I am glad that manufacturers have provided the opportunity to use them when working at a computer due to the increased image contrast and in a car (even at night).

1 Top Vision ASP 1.67 Transitions XTRActive HMC

Maximum dimming in light (90%)
Country Russia
Average price: 9900 rub.
Rating (2019): 4.9

Lenses designed specifically for active people. In bright sun they darken by 90%, which is the best indicator compared to all other models. This is a spherical plastic lens with diopters from -10 to +8.75 and a cylinder from -4 to +4. It is single vision and very thin - the refractive index is only 1.67. There is also a spherical version, but it is noticeably thicker (IP is only 1.5). There are two colors on sale - brown and gray.

There is a multifunctional multilayer coating HMC, which has several properties at once. It eliminates glare, repels moisture and dirt, is antistatic and incredibly durable. Manufacturers have made sure that the model can also be used in a car - it is darkened by 50%, so now driving will become noticeably more pleasant even in sunny weather. But it is worth remembering that the initial darkening of such a lens is 11%, so the tint will be visible even indoors.

How is photochromism used in optics? What are chameleon glasses? What are their advantages?

A person indoors wearing transparent glasses reads or looks into the distance, and when he goes outside, the lenses instantly become dark and protect his eyes from the sun. Magic? Not at all! Elementary photochromism.

Tags medicine glasses glasses lenses vision vision correction lens coatings

Smart molecules

The phenomenon of photochromism is based on the ability of the molecules of certain substances (for example, silver and copper) to change their structure under the influence of ultraviolet radiation. In their initial state, these molecules have high degree light transmittance (the glasses are transparent), but as soon as UV rays hit them, they are activated and transmit much less light (the glasses become gray or brown). If the sun disappears, the molecules return to their original state, and the glasses again turn colorless.

It's comfortable. Firstly, vision correction occurs continuously. Secondly, you don’t need to take off your glasses and put on sunglasses when going outside and do reverse process, entering the room.

The phenomenon of photochromism was discovered at the end of the 18th century. In the twentieth century, not only physicists, but also manufacturers of spectacle lenses became interested in it.

In 1964, Corning Glass Works released the first photochromic-coated lenses, Photolite. These were glasses from glass lenses, on which silver and copper halides were applied. In the 1980s, photochromic coatings began to be applied to organic lenses.

But the real “revolution” occurred in 1991, when PPG Industries and Essilor International merged (Transitions Optical) and jointly developed Transitions technology. This technology has become one of the most popular.

Glass or plastic - what to choose?

Mineral (glass) and organic (plastic) photochromic lenses differ in the production method and some properties. Therefore, the question often arises - which is better?

In glasses with mineral lenses, the photochromic elements are “inside” - they are added when the glass is melted. On organic lenses, photochromic molecules are usually applied “on top”.

In terms of properties, modern inorganic and organic lenses with photochromic coating are practically indistinguishable from each other. However, polymer spectacle lenses “darken” more evenly; in mineral lenses, darkening sometimes “accumulates” along the edges or in the center of the lenses.

In principle, it is not so important what material the glasses are made of - lenses with photochromic coating will in any case protect the eyes from ultraviolet radiation.

Alone instead of a couple

Many people choose glasses with photochromic coating, believing that they will replace prescription glasses and sunglasses. This is true if you alternate between being indoors and outdoors.

Depending on the type of photochromic lenses, they can provide up to 90% darkness, which means they are, in principle, suitable for wearing on the beach. However, most often photochromic lenses are inserted into frames for permanent wear, which are smaller in size than the frames of beach glasses. But this is a matter of aesthetics and personal preference.

The “behavior” of photochromic lenses depends on the air temperature: they darken in the heat, but more slowly and less; in cold weather, on the contrary, the darkening occurs more intensely.

Manufacturers of spectacle lenses are actively working to improve photochromic coatings. Over a million chameleon glasses are sold annually, and demand is only growing. Photochromic lenses are emerging for people who spend a lot of time driving or outdoors, in bright sunshine and at high temperatures. These lenses provide greater darkness and maintain it in hot weather.

There are also lighter photochromic lenses for people who spend a lot of time indoors. Tinted photochromic lenses and lenses with unusual curves are appearing for fashionable frames.

Overall, it is now easy to find photochromic lenses that will suit your lifestyle and the frames you want to wear. And modern coatings will help protect your eyes from UV rays and bright light.

Chameleon glasses can replace two pairs of glasses at once for people with reduced vision. Photochromic glasses are designed specifically for ease of use in indoor environments. to varying degrees illumination and sunlight. Chameleon lenses are made of an innovative material that can react to ultraviolet A and B. Let's consider all the properties of photochromic optics and the main advantages.

The principle of operation of photochromic optics

The main purpose of chameleons is to change the degree of darkening of the lenses depending on the brightness of the light. In the sun they darken, indoors they acquire the properties of ordinary glasses with transparent lenses. Changing the color of the lenses is provided by photochromic elements that are sensitive to ultraviolet radiation and light intensity.

Lenses work as a filter, allowing a certain amount of light rays to pass through. Thus, they protect the eyes from excess rays. However, photochromic glasses are not designed for prolonged exposure to bright sun. On the beach, it is recommended to use regular sunglasses with a constant degree of darkness.

In modern optics, they have achieved leveling of the temperature factor: lenses work perfectly at any temperature difference, do not fog up and do not lose their photosensitive qualities.

Indications for use photochromic glasses:

• patients with poor eyesight;
• dystrophic thinning of the retina;
• prevention of cataracts;
• UV protection.

Photochromic optics are also suitable for anyone who spends a lot of time in the sun: athletes and fishermen, drivers and tourists. Athletes can purchase special glasses with diopters.

Advantages of using photochromic optics:

• eye protection from UV radiation;
• comfortable view of the space;
• can be used indoors and outdoors;
• prevention of eye diseases;
• versatility of application.

Photochromic glasses can be used by people with various visual impairments. The degree of darkening of lenses varies from 15% to 85%, the distribution of photochromic agents in lenses also has its own characteristics.

Optical products are based on two lens manufacturing technologies - the distribution of photochrome to a certain depth and the uniform distribution of agents throughout the entire mass of the material.

Photochromic glasses are especially convenient for people with visual impairments. Previously, they were required to have two pairs of glasses - for outdoors (with diopters) and for indoors. This problem has now been completely resolved.

Photochromic lens material

The modern optics market offers a wide range of high-quality spectacle lenses with a photochromic effect. However, before purchasing optics, you should visit an ophthalmologist and have your vision checked, as well as get advice on choosing the right pair of glasses.

Lenses for photochromic optics can be made of organic or inorganic material (mineral glass), the degree of refraction of rays also differs different models. What is the difference between these materials?

Mineral (inorganic) photochrome is evenly distributed in liquid glass during cooking. Organic lenses are made in several ways:

• volumetric distribution of photochrome in the mass;
• impregnation (imbuing);
• application of photochromic coatings.

The method of introducing photochromic agents into the mass has been used for a long time and is not developed by any company. It is widely used in SunSensors technologies.

Impregnation technology (imbibing) involves introducing agents in a uniform layer to a thickness of 0.15 mm. Then the surface of the lenses is covered with a protective layer. This technique is widely used by Transitions Optical.

Method of applying photochromic coatings - on front side A conventional lens, which does not require any modification, is coated with photochrom. A special hardening coating is used to fix the photochromic layer.

Modern lenses are impact-resistant, elastic and environmentally friendly. The versatility of the new material provides a good degree of dimming in bright light and absolute transparency in the room. The color of photochromic optics is either gray or brown.

Photochromic lenses for glasses can be supplemented with a multifunctional coating, providing additional comfort. The design is varied and unique. Some expensive models can become a real accessory for creating an image.

Photochromic glasses for glasses are different best performance refraction than organic materials, are not subject to deformation when high temperatures and scratching. However, this material is heavier than polymer, so it is not recommended for use by athletes and children.

Technologies for manufacturing spectacle lenses

Technology Transitions

This technology is based on the introduction of photochromic agents to a given depth of the lens body. This method used by some foreign optical companies - Essilor, Hoya, Sola, Zeiss, Seiko.

If you spend a lot of time outdoors, invest in Transitions Signature sunglasses. The lenses of these products quickly react to radiation flows, changing their tone. Inside the room, the glass becomes completely transparent, like ordinary glasses. On the street, in a bright stream of sunlight, the lenses provide a comfortable view, relieve eye strain, and absorb glare.

If your eyes are sensitive to light, you should choose the Transitions XTRActive brand. This optic is characterized by strong darkening in the light, and in a closed room with bright lighting it retains a pleasant smoky tone. Also, glasses are well suited for drivers, as they tend to absorb solar flow behind the windshield and fight glare.

Transitions Vantage brand glasses are recommended for people with great sensitivity to sun rays. Glasses are suitable for those who spend a lot of time outdoors. Indoors, the lenses become completely transparent. With Vantage brand optics, your eyes are protected from glare, intense sunlight and bright indoor lighting. In addition to protection, optics provide clear images of objects.

SunSensors Technology

SunSensors optics have gained recognition among Russian consumers due to the uniform distribution of the photochromic agent throughout the entire thickness of the glass. 3D colored lenses (solid photochrome) are made from highly refractive materials that provide maximum visual comfort. This technology is used by Hoya, Rodenstock and Kodak.

Recently, a new technology, SunSensors HPC, was invented to compete with Transitions. Distinctive feature new technology is the service life. While some photochrome molecules lose their original properties, others replace them. The lenses absorb the entire spectrum of dangerous ultraviolet B, reliably protecting the eyes from diseases. The lenses also neutralize up to 97.5% of ultraviolet A.

The material used to make the new lenses (plastic photochrome) is lightweight and comfortable. SunSensors HPC instantly responds to changes in light, gently changing the color of the glass from dark to transparent.

Photochromic glasses for drivers

What are photochromic glasses for drivers? Manufacturers produce Transitions DriveWear glasses, which are designed to absorb rays inside the car. Initial degree The darkening of such products corresponds to 50%; in bright sunlight, the lenses retain up to 89% of the light flux. The optics were developed jointly by Younger Optics and Transitions.

The difference between regular glasses and photochromic glasses is the ability of the lenses to retain both ultraviolet radiation and blue rays of sunlight. The optics protect the driver from blinding glare while driving on the highway. In addition to their protective properties, glasses increase the clarity of visibility of road objects, relieve eye strain, and provide high visual comfort.

These glasses change color depending on the light level. In cloudy weather they become yellowish-green, in the car interior they become copper, and in bright sunshine outside they acquire a brown tint. Their light absorption capacity also changes - from 65% to 89%.

Bottom line

The modern optical industry is developing rapidly, improving its products to increase ease of use. Photochromic glasses for glasses are produced to protect the eyes from an excessive flow of harmful solar radiation, which protects a person from possible diseases visual organs.

The convenience of photochromic optics lies in the ability to change the degree of refraction of rays using darkening/brightening of light-sensitive lenses. Now there is no need to wear two pairs of glasses (indoors and outdoors), since photochromic agents cope with any degree of illumination.

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Glasses with photochromic lenses have another name - chameleons, since they can change their color directly depending on the lighting. IN dark time days or indoors, they have practically no differences from ordinary colorless lenses or may have an unexpressed initial tint.

On the street, such glasses darken on their own, and in sunlight they practically turn into sunglasses. If you go into any room, the photochromic glasses will again become transparent.

Principle of operation

Such properties of chameleon glasses can be explained by the presence of special substances with a photochromic structure in the lenses. Under the influence of ultraviolet radiation, their spatial structure changes, they cease to transmit light, as a result, the lenses darken.

In the absence of ultraviolet light, the opposite changes occur, and such a lens becomes transparent again.

Until recently, the rate of darkening of such glasses depended not only on the degree of illumination, but also on the ambient temperature. Darkening occurred more quickly in the cold than at high temperatures, and on very hot summer days the lenses may not reach the maximum degree of darkening.

Photochromic lenses, which are produced using modern innovative technologies, the speed of the processes of clearing and reverse darkening, as well as the degree of darkening, have practically no dependence on the ambient temperature.

Manufacturing technologies for photochromic glasses

In most cases, photochromic lenses in a darkened state come in two shades - brown and gray, and the maximum darkening indicator can vary: from weak (10-15%) to strong (80-85%).

Photochromic lenses can be produced using various technologies. For example, according to Technology Transitions, photochromic substances are evenly distributed over the surface of the lens to a certain depth. Most well-known manufacturers, such as Sola, Zeiss, Seiko, Essilor, Hoya, produce photochromic lenses using this technology.

At the core SunSensors technologies, the distribution of photochromic substances is carried out throughout the entire mass of materials from which the lens is directly produced. Such products are called volume-colored. A number of companies also use a similar method to create their photochromic lenses.

Hoya, Kodak and Rodenstock produce eyeglass lenses from their own polymer materials with photochromic agents distributed throughout the mass.

Benefits of photochromic glasses

Photochromic glasses are ideal for people with poor vision. Such people either purchase prescription sunglasses and, when going out into bright sunlight, are forced to change them, or wear tinted glasses. Chameleons can replace several pairs of glasses.

In a glassed room, photochromic lenses do not darken, since glass is not capable of transmitting ultraviolet radiation, so such glasses also “do not work” in a car.

Therefore, drivers wearing glasses for vision correction and in sunny weather need to use sunglasses with diopters, or use special clip-on attachments for glasses.

But recently, many well-known companies have begun to produce photochromic lenses that can darken not only under the influence of ultraviolet radiation, but also under the action of short-wave blue rays of the solar spectrum, penetrating directly into the interior of the car.

In addition to the fact that fluorochromes provide one hundred percent protection from dangerous ultraviolet radiation, they provide the light transmission necessary for the eyes, reacting to the slightest changes in illumination on the street, while straining the eyes and visual fatigue decreases, visual contrast increases. This is extremely important for those who have increased tear production or have.

In addition to visual convenience and comfort, photochromic glasses also have certain medical indications:

• as an alternative to sunglasses
• they are recommended to patients suffering dystrophic diseases retina
• reduce the likelihood of developing cataracts

Photochromic lenses can be either polymer or mineral, including polycarbonate. The buyer has the opportunity to choose any refractive index for his photochromic glasses; if necessary, they can be made more sophisticated.

Photochromic lenses are sometimes coated with a special multifunctional coating, giving the glasses the necessary beneficial features. Modern glasses are available in absolutely any design: aspherical, traditional monofocal, progressive.

Photochromic lenses are very popular among buyers who want to have glasses that not only provide high vision performance, but also reliable protection from solar radiation.