Photochromic lenses are a special type of lenses that react to ultraviolet radiation and due to this they can be shaded depending on the intensity of the radiation, or clarified if the intensity of the radiation decreases. Indoors they are transparent and you can use them like normal reading and computer glasses for any kind of work indoors. When you go outside, the lenses are exposed to ultraviolet radiation and darken. Thus, they begin to fulfill the role of sunglasses, protecting your eyes from both ultraviolet radiation and the blinding effect of sunlight.

What are the best photochromic lenses?

In terms of material, today we have a choice between plastic lenses and glass lenses. Glass lenses are available to us only in the so-called photochromic mass. Photochromic means that photochromic is present in the entire mass of the lens.
What does it give? this gives fairly good photochromic properties with a small lens thickness. When the thickness of the lens is large (lens plus 6), then due to the difference in thickness from the center of the lens to the edge of the lens, the photochromic elements react at different rates. Thus, it turns out that the photochromic reacts faster along the edge than in the thick center. In this case, we get a not very good effect, when the photochromic begins to act only at the edges and very slowly reaches the center. Thus, the uneven darkening of the lens does not give the consumer the desired effect, the desired darkening speed. Recall that a plus lens will darken faster around the edges because it is thinner at the edge and darken slower in the center because it is thicker in the center. The minus lens, on the contrary, will darken faster in the center, since the minus lens is thin in the center, and darkening will be slower at the edges, since the edges of this lens, on the contrary, are thicker. Such a lens meets all the characteristics of a photochromic lens - it completely protects our eyes from ultraviolet radiation, but does not fully satisfy us with the speed of dimming and thus does not fully satisfy our aesthetic needs, that is, its cosmetic effect is reduced.
It is also important to note that there is another disadvantage to mineral lenses and this disadvantage is associated with the choice of frames. We can't put mineral lenses in woodline frames and rimless frames because the lens is brittle and will easily break if we try to put it in this type of frame.

Plastic lenses do not limit us in choosing the type of frame. We can insert them both in ordinary - rimmed, and in forest and rimless frames. Plastic lenses give us much more freedom.

Modern technologies make it possible to use the so-called photochromic coating film technologies and thus fully satisfy our requirements in terms of aesthetics, clearing speed and other characteristics. World manufacturers that use the latest technologies apply the so-called photochromic film, which is applied as a separate layer on the lens and when exposed to sunlight, the photochromic layer reacts, and not the entire mass of the lens.

What benefits does this provide for the user?

The first is the fastest darkening and the fastest clearing, because a very thin layer reacts.

Second, darkening and clearing occurs evenly over the entire surface of the lens, regardless of the thickness of the lens and regardless of whether the lens is plus or minus.

Third, a polymer lens is lighter and less traumatic than a glass lens. When the lens is deformed, there is no such high degree of risk for the spectacle wearer.

Plastic or glass lenses? which lenses are best?

Spectacle lens wearers today have a fair amount of choice in terms of both price and the technology they can incorporate into their glasses. Mineral glass lenses are more affordable, the cheapest, but heavier, and at the same time more traumatic.

Plastic lenses are lighter, more aesthetic, less traumatic, but as they use more modern technology, they become more expensive and less affordable. At the same time, both plastic and mineral lenses equally protect our eyes from harmful ultraviolet rays.

One of the biggest concerns of photochromic lens manufacturers in recent times has been how to reduce the temperature dependence of the lens, especially during hot weather. That is, if in the cold at low temperatures the lens works perfectly, there have never been complaints about this, then in hot weather, when the lenses are most in demand, the lens, on the contrary, did not fully meet our expectations, that is, it was not darkened by 60-70%, as it should, and by 30-40%, maximum 50%.
The new generation lenses are less temperature dependent and therefore even in hot weather, somewhere in a hot climate where the sun is intense, they darken better and more meet the expectations that we set for them. Novelties in the field of photochromic lenses are lenses called Transition Extra Active, which are offered by French manufacturers. These lenses react not just to ultraviolet, these lenses react to the visible spectrum of light radiation, that is, they are able to darken to a certain extent even if the action of ultraviolet is not direct, but simply solar radiation acts on the lens. Thus, these lenses work also behind the windshield of a car and they can work even in a room where there are very large stained-glass windows, large windows.

In addition, manufacturers of photochromic lenses have prepared another surprise for users - photochromic transition lenses of the new generation, already the 7th in a row. By and large, this is an improved version of previous photochromic lenses with new technologies, new developments that allow these lenses to clear up faster in the room and darken faster.

Many people have vision problems. A certain part of them has uncomfortable sensations on a sunny day. In such a situation, it becomes necessary to use glasses or lenses. One of the latest ways to deal with bright light are chameleon glasses, which can be worn literally everywhere - even on the street, even indoors.

What it is

Chameleon glasses are products with photochromic glasses that can change the degree and tone of darkness depending on the amount of rays falling on the lens surface. They are brightened in the building when the amount of sunlight is minimized. The goggles protect your eyes from ultraviolet rays. Such accessories can be with or without diopters. Therefore, both people with low vision and those with normal vision can wear them without constantly changing glasses or wearing soft contact sun protection products.

How special glasses work

Chameleon glasses are suitable for those people who have an increased sensitivity to blinding light. Because of this, unpleasant symptoms are often manifested in the form of redness of the eyes, photophobia and tearing. Since they combine several types of vision accessories at once, the process of using them is greatly simplified.

Their frames are either metal or plastic. Metal ones are considered lighter. But the lenses themselves for such glasses should be made of glass, since only on their surface can a real high-quality photochromic layer be created to protect against UV rays.

What a black dot looks like in the eye and what can be done with such a disease is indicated in this

According to the degree of darkness, they are divided into three types:

Weak form;
Medium form;
Reinforced form.

On the video - how glasses with special lenses work:

The weak form is represented mainly by brown glasses. Absorbs only 15% of incoming rays. Such models are most often worn by women. The medium shape absorbs up to 60% of the light. These models are preferred by people who love walking on sunny days, as well as by drivers. Glasses of this type have a gray tint. The reinforced form absorbs up to 80% of the rays, and the lenses have a greenish tint. This model is most suitable for those people who often suffer from conjunctivitis, increased sensitivity to light, dryness and pain.

In the process of choosing such glasses, make sure that you are comfortable in them and the available shade does not strain your eyes. All shades should look as natural as possible!

But what to do when your eyes are very sore from a computer and what means should be used is described in great detail.

How to use

Doctors recommend, if there is no indication, to give preference to the average degree of darkness. It is they who can cope with the adjustment and protection of the organ of vision. Such products are quite durable and have a long service life. In the process of buying, you should understand that fakes are often distributed under photochromic chameleon glasses.

What you need to know about such products in order to use them correctly as a result:

The real lens has a dark edge. With a light shade of the rib, we can simply talk about the applied coating, which will quickly be erased. That is, such glasses are not photochromic.
High-quality glasses do not cause distortion of color perception. When faked, the colors will seem unnatural.
The protective layer of sputtering must always be applied evenly, otherwise we can talk about poor-quality performance of the product and a fake.
In the presence of vision problems, the buyer should immediately purchase glasses with diopters. And for this you need to visit an ophthalmologist, who will write out the desired prescription. In optics, such glasses will be made to order.
Lenses need to be changed every couple of years.. The lens coating loses its function over time and the product stops working in the desired mode.
Care of the product is the same as when using conventional accessories of this type.– every day the surface is wiped with a special cloth, the glasses themselves are stored in a case, and the lenses are placed on the surface to the top.

You may also find it useful to know which ones are worth using and what their cost is.

On the video - how to use glasses correctly:

If we talk directly about the use, then there is nothing complicated - put it on and wear it to your health. It is not necessary to shoot them outdoors and indoors, as the color of the glasses changes depending on the light. Accordingly, the glass in the building becomes transparent, like ordinary glasses.

It will also be useful to learn about how to use and what effect they can bring from use.

Price

The cost for different products depends on the quality, brand and other indicators, as well as related accessories for chameleon glasses. Also, the cost is affected by the materials used in the manufacture of this product:

Photochromic glass lenses:
Korean-made glasses with and without diopters cost from 2030 to 2900 rubles. This price range is due to the presence or absence of anti-reflective coatings, as well as what lenses are used to produce them. Astigmatic glasses are the most expensive. In terms of quality, they are generally not inferior to expensive brands, especially in relation to optical indicators. but their scratch resistance is not as high as that of expensive glasses, and therefore they are significantly inferior in this matter. The main disadvantage is the slow enlightenment in the room after the abundance of sunlight on the street. Sometimes the process takes almost 4 minutes, which naturally creates discomfort during use.
Korean made glasses
Photochromic vintage lenses from Carl Zeiss model Umbramatic Brown Gold ET cost about 5300 rubles for a pair of lenses. Their pre-darkening is 15%, and the darkening color is brown. Indoors, the lens will have an almost imperceptible brownish tint. Among users, this model has proven itself from the best side. The clarification process is about 2 minutes, which fully complies with modern standards.
Photochromic polymer lenses made of plastic:
Korean-made polymer lenses start at 3,700 rubles. These are products with an anti-reflective coating and nothing more. With diopters, products can cost more. Chameleon glasses with astigmatism of a given manufacturing country can reach a cost of 6800 rubles. Such products have high resistance to scratching of the lens surface. But at the same time, the main drawback remains - up to 5 minutes, enlightenment in the room continues.
An analogue of the previous paragraph is Korean lenses with a refractive index of 1.6. They are thin aspherical lenses. The cost starts from 5100 rubles for a pair of lenses.
Corning launches Sunsensors glasses. For a pair of lenses of a non-toric type, that is, ordinary ones, they offer a cost of 4800 rubles. Astigmatic lenses are made to order and therefore the cost is specified with consultants. The enlightenment process lasts 3 minutes, and the scratch resistance of such an accessory is one of the highest among analogues. It will also be interesting to learn about whether it is necessary to constantly wear glasses with presbyopia and what effect can be achieved from
Another model from Carl Zeiss - Clarlet Transitions VI LotuTec. For a pair of lenses, they charge from 8,000 rubles. They have high protection against mechanical damage due to the top layer of the protective coating, as well as increased durability of the reagents in the lenses. The enlightenment time is 1.5-2 minutes. But what glasses should be used for strabismus in children and how to choose the right ones is indicated.
Japanese plastic lenses from Seiko company model AR-Diacoat Transitions VII have similar properties. But they are also much more expensive. They take from 8600 rubles for one pair. But what kind of glasses should be used for strabismus in adults and how much they can help. stated
Altolite Transitions VII XTRActive from the Israeli company Shamir are ideal for drivers. For a couple they take 8900 rubles. They tend to darken under the windshield of a car up to 60%, and on the street - up to 85%. Designed specifically for motorists, these lenses feature 8% pre-tint and a high-quality multi-layer coating that makes even driving at night comfortable and safe. It will also be useful to learn how to properly use

Before purchasing a product, make sure that you are not being offered a fake. These glasses must be certified.

It will also be useful to learn about in which case glasses with holes are used to improve vision and what are

Photochromic lenses for glasses. Characteristics and protective properties of photochromic glasses

Glasses with photochromic lenses are often called chameleons because they change color depending on the light. Indoors or at night, photochromic lenses do not differ in any way from ordinary colorless spectacle lenses or have a slight initial tint.

On the street, such glasses are darkened by themselves, almost turning into sunglasses in very bright sunlight. If you enter the room, the photochromic glasses become transparent again.

How photochromic lenses work

Such properties of chameleon glasses are explained by the presence of special photochromic substances in the lenses. Under the action of UV radiation, their spatial structure changes, while they stop transmitting light and the lens darkens. In the absence of ultraviolet light, the reverse changes occur, the lens becomes transparent again.

Previously, the speed of darkening of photochromic lenses depended not only on the degree of illumination, but also on the ambient temperature. In the cold, darkening occurred more quickly than at very high temperatures. So on a very hot summer day, the lenses might not reach their maximum darkening.

For photochromic lenses produced using the most modern technologies, the speed of the processes of darkening and enlightenment, the degree of darkening are much less dependent on the influence of ambient temperature.

Manufacturing technologies

Photochromic lenses in a darkened state, as a rule, come in two shades - gray and brown, and the degree of maximum darkening can also be different: from weak darkening (10-15%) to strong (80-85%).

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

According to SunSensors technology, photochromic substances are distributed throughout the mass of the material from which the lens is made, such lenses are also called volume-colored. And also a number of companies use this method for the manufacture of their photochromic lenses.

Hoya, Rodenstock and Kodak manufacture spectacle lenses from their own polymers with a mass-distributed photochromic agent.

Benefits of photochromic lenses

Photochromic glasses are ideal for people with poor eyesight. Such people usually have to either purchase sunglasses with diopters and, when going out into bright light, change glasses or wear tinted glasses. Chameleons replace two pairs of glasses: regular + sunglasses with diopters.

Chameleons replace two pairs of glasses: regular and prescription sunglasses

Photochromic lenses do not darken in a glazed room, as the glass does not transmit ultraviolet light, so photochromic glasses also "do not work" in a car. Recently, however, some well-known companies have begun to produce photochromic lenses that can darken not only under the influence of ultraviolet, but also when exposed to short-wave blue rays of the solar spectrum that penetrate the interior of the car.

Thus, drivers who wear glasses for vision correction, and in sunny weather must either use sunglasses with diopters, or use special clip-on glasses, got the opportunity to comfortably drive a car in any weather without thinking about changing glasses.

In addition to 100% protection from harmful ultraviolet radiation, photochromes provide the light transmission necessary for the eyes, reacting to changes in street lighting, while reducing eye strain, visual fatigue, and increasing visual contrast. This is especially important for those who have developed photophobia or increased lacrimation.

In addition to visual comfort and convenience, photochromic glasses also have medical indications: as an alternative to sunglasses, they are recommended for patients suffering from degenerative retinal diseases and reduce the risk of cataracts.

Photochromic lenses can be either mineral or polymer, including polycarbonate. You can also choose almost any refractive index for your photochromic glasses, making them more subtle if necessary.

Photochromic lenses can be coated with a multifunctional coating that gives the glasses the properties you need. Modern photochromic glasses are available in any design: traditional monofocal, aspherical design, progressive.

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

Most people have difficulty with vision, and some experience discomfort in bright and sunny weather. In such a situation, to protect the eyes, they need lenses or glasses.

One of the modern devices can be called chameleon glasses. They are worn in any light, put on the street and do not take off indoors.

Chameleon glasses have photochromic glasses, which are lenses that can change the tone and degree of darkness depending on the amount of sunlight. The lenses are brightened the moment a person is in the building, as the amount of UV rays received is minimized. When you go outside, the glass darkens, trying to protect the visual organ from exposure to a large amount of light.

Chameleon glasses have the main feature, which is the presence and absence of diopters. That is, they can be worn by people with poor eyesight.

The degree of shading of chameleon glasses

Chameleon glasses are great for those people who have an increased susceptibility to blinding light. Often because of this, they suffer from photophobia, tearing and redness of the eyes. Such glasses combine several types of products at once, which facilitates the process of their use. This saves a person from wearing soft lenses at the same time and constantly changing one glasses for others.

The frame of accessories can be made of any material: plastic or metal. It is believed that metal products are much lighter and more convenient to use. But the lenses themselves must be made of glass, since it is such a material that helps to create a real photochromic plane.

According to the degree of darkness, the glasses are divided.

in weak form. They absorb up to fifty percent of the light. They have brown lenses. Often these models are worn by the female half of the population.
For medium shape. Absorb light from fifteen to sixty percent of the light. Such models are perfect for walking on the street and for those people who drive a car. They have gray glass.
For enhanced form. Absorb up to eighty percent of light rays. The lenses are green. Basically, these models are used by patients suffering from conjunctivitis, increased susceptibility to light, pain and dryness.

Experts say that it is better to choose chameleon glasses with an average degree of darkness. After all, they do an excellent job of correcting vision and protecting it, while the products have a long service life and are quite durable.

Chameleon glasses for drivers

Chameleon glasses can also be used by drivers who are constantly driving. For their manufacture, photochromic type lenses are used, which tend to change color depending on the illumination. For drivers, this accessory will be just a godsend, because the visual organ will always be protected without any damage.

Modern glasses are able to protect the eyes as much as possible in the car. Glasses contain substances that regulate not only ultraviolet radiation, but also absorb blue light spectrum, which is contained in the sun's rays. The lenses can darken up to eighty percent, which will allow you to control the situation on the road even in bright blinding light.

Such lenses are a great find for drivers who have problems with visual acuity. After all, simple products with diopters do not protect against glare and bright sun. Chameleon glasses are a replacement for several accessories at once.

A few years ago, glasses were not in such demand among people, as the quality of the lenses was poor. But more recently, lenses made of high-quality material with diopters began to arrive in stores.

Popular models of chameleon glasses for men and women

Sunglasses chameleons can be divided into two types: men's and women's. Products for the female half of the population have a more elegant look, while they are small in size, sophisticated temples and frames with various decorative elements. Men's glasses have not so many varieties. They differ only in their massiveness and variety of frame shapes.

Instructions for choosing the right chameleon glasses

To buy glasses, you need to be able to distinguish high-quality work from inexpensive counterparts. To do this, you should follow a few recommendations.

A real lens has a dark edge. If it is light, it means that the glasses are only coated and they are not photochromic.
If you look through high-quality glasses, they will not distort color perception. If you have a fake in front of you, then the naturalness of the colors will be violated.
A good quality spray will lie perfectly flat. If it is badly applied, then such glasses are fake.
If the buyer has vision problems, then glasses must be purchased with the presence of diopters. To do this, you should contact an ophthalmologist to check your eyesight. The doctor will write out a prescription, according to which glasses will be made to order in optics.
Lenses need to be replaced every two years as the coating loses its function and gradually wears off.
You need to take care of them in the same way as you would for ordinary accessories. Wipe daily with a special cloth, store in a case and place on the surface with the lenses up.

The price of chameleon glasses in stores

The cost of sun protection.
The price of chameleon glasses depends on several parameters.

What material are the lenses and frames made from?
The presence of decor.
The presence of diopters.
Producer reputation.
Shop pricing.

On average, the price of high-quality models ranges from one to two thousand rubles. If we talk about accessories from well-known companies, then their price goes from two to five thousand rubles. But there are fakes on the market that cost much less. Good glasses are absolutely safe for the health of the buyer's eyes. But a fake not only does not affect the image quality, but also harms the eyes, not holding ultraviolet and anti-glare rays.

Notes on choosing glasses

It is worth noting the fact that modern models can be chosen for any style of clothing and image. Naturally, chameleon glasses should be selected, taking into account several circumstances - the season, the shape of the face and the type of clothing. For example, for people with a round and wide-cheeked face, models in the shape of a cat's eye and a fox with glasses, narrowed upwards, are perfect. Narrow-faced people need to visually expand the face, so they should choose glasses with a square shape of small sizes. To all this, for men's accessories, the frame should be much more massive than for the female half.

Glasses of an elegant type will go well with evening dresses, especially with classic clothes. In the summer, you should pay attention to lightweight glasses that have a light-colored frame. If the buyer prefers an active winter holiday, then you need to select products with a large view and an anti-glare coating.

Also, glasses can be matched to the color of accessories or clothing, to the shade of the eyes or hair. Today, glasses are not just a method of vision correction, but also a stylish element in the image.

Photochromic lenses- these are lenses that not only correct vision (improve vision to the maximum visual acuity achievable with glasses), but also change the degree of their dimming depending on the intensity of sunlight. Glasses with photochromic lenses are called photochromic glasses, as well as "chameleon" glasses.

Photochromic lenses can be colorless indoors, like normal spectacle lenses, but they quickly darken outdoors in bright sunlight. Photochromic glasses outdoors protect your eyes from excess sunlight in the same way that sunglasses do. If you enter the room from the street, then photochromic lenses quickly become colorless again. Indoor photochromic lenses are virtually indistinguishable from ordinary colorless glasses used to correct refractive errors.

Such "smart" behavior of photochromic lenses is explained by the presence of molecules of special photochromic substances in their material. The molecules of these substances under the influence of ultraviolet radiation, which is an integral part of the solar radiation spectrum, pass from the initial state, characterized by a high degree of light transmission, to the activated state, in which they already transmit much less visible light rays. The photochromic lens becomes darker when activated (usually it becomes gray or brown). When ultraviolet radiation ceases to act on photochromic lenses, the molecules of photochromic substances spontaneously return to their original state and again transmit all visible light. The lens becomes colorless again.

On a sunny day, photochromic glasses on the street replace prescription sunglasses, and indoors they are no different from ordinary glasses for vision correction.

Photochromic eyeglass lenses Transitions

Photochromic spectacle lenses appeared on the optical market in the 1990s, when Transitions photochromic technology was developed and the first photochromic eyeglass lenses Transitions made using this technology.

Transitions spectacle lenses quickly gained wide popularity. Transitions technology is used to manufacture spectacle lenses from many manufacturers, including world leaders: Essilor, Hoya, Sola, Zeiss, Seiko. These companies supply their finished colorless spectacle lenses to factories where they are given photochromic properties by incorporating photochromic molecules into the surface layer of the lens. From there, the lenses of these and other companies, which have already become photochromic, are returned to customers.

The latest Transitions VI technology is now on the market, which differs from the previous (five) generations with improved characteristics. Indoors, these lenses are as colorless as, for example, reading glasses: they let through almost 100% of the rays falling on them (if there is a high-quality anti-reflective coating on the spectacle lens). Transitions VI photochromic lenses darken faster outdoors and return to their original colorless state faster than their predecessors. Moreover, the speed of these processes and the degree of darkening in the lenses of the latest generation are less dependent on the influence of temperature.

The fact is that at very high temperatures (for example, under direct sunlight on the beach), photochromic lenses, although darkened, are much less than sunglasses. This is due to the effect of temperature on the properties of the applied photochromic substances. In cold sunny weather (minus), photochromic lenses, on the contrary, will be very dark outside, and they brighten more slowly when exposure to ultraviolet radiation stops.

Transitions VI photochromic lenses are made from all resins, from standard plastic (CR-39) to the highest refractive index resin of 1.74 available today.

Transitions VI photochromic lenses are available in any optical design - single vision, bifocal and progressive.

Photochromic eyeglass lensesSunSensors

In addition to Transitions VI photochromic lenses, there are other photochromic lenses on the optical market. SunSensors photochromic lenses are very popular in Russia. These lenses are made from a polymer in which the photochromic agent is distributed throughout the mass (sometimes referred to as volume-colored photochromic lenses) rather than concentrated in the surface layer of the lens, as in Transitions spectacle lenses. SunSensors photochromic material is manufactured by Corning and a number of companies use it to make their photochromic lenses. Recently, Corning introduced its technology to inject a photochromic agent into the surface layer of a lens, and SunSensors HPC photochromic lenses are now on the market to compete with Transitions photochromic lenses. SunSensors HPC lenses are made from highly refractive materials with a refractive index of 1.6 and 1.67 and polycarbonate.

Spectacle lenses made from proprietary polymers with a mass-distributed photochromic agent are also offered by Hoya, Rodenstock, and Kodak.

Transitions spectacle lenses and spectacle lenses with a volumetric distribution of a photochromic agent are mainly available in two colors: gray and brown. Moreover, these two types of spectacle lenses differ somewhat in the rate of change in light transmission and the maximum degree of darkening.

Photochromic glasses replace two pairs of regular glasses

Modern photochromic spectacle lenses can be recommended as an alternative to any untinted spectacle lenses indoors. However, they can also be used as sunglass lenses, as they attenuate the bright rays of the sun. Thus, one pair of photochromic glasses can replace two ordinary ones: indoor and sunglasses. They are ideal for situations where you alternate between being outdoors and indoors on a bright sunny day.

However, photochromic lenses are not a complete replacement for sunglasses if you plan to spend the whole day under the sun, for example, on the beach. For reliable protection of the eyes from too bright sunlight during prolonged exposure to the open air, they are best suited with a constant degree of dimming.

Photochromic glasses for drivers

We also note that ordinary photochromic glasses do not darken in the car interior, since ultraviolet radiation practically does not penetrate through the windproof glass of a car (modern glasses absorb ultraviolet radiation almost completely).

In general, the sector of photochromic spectacle lenses is now one of the fastest growing in the optical market, it is increasingly appearing new products with better photochromic properties; More and more companies offer their photochromic eyeglass lenses. The latest generation photochromic spectacle lenses, such as Transitions and SunSensors, certainly offer a very high level of visual comfort. They really allow you to replace two pairs of glasses (simple and sunglasses) with one - with photochromic lenses.