How doctors choose glasses for vision. How to choose glasses that are perfect for your face type. Sizes for frames, what they are needed for and how to view them

In theory, glasses should not only improve vision, but also match your appearance, and ideally, even serve as decoration. Therefore, the question of how to choose glasses for vision is very relevant.

In practice, if you choose the wrong glasses, in which you can see everything perfectly, after a while they become the cause of headaches and even fatigue. The easiest advice for a buyer is to see a doctor for a prescription. But the doctor cannot know all the nuances, and the buyer experiences the choice over several years. How to choose glasses for vision?

How to choose the right glasses for vision?

That's just short list what to focus on when choosing:

• The material from which the lenses are made is (plastic or glass). This item affects total weight glasses and the load on the bridge of the nose, as well as the cleanliness of the lens surface throughout the entire service life (the glass is less scratched). It is advisable to take into account the safety of plastic and its resistance to impacts when dropped.
• Frame material: metal, plastic (reinforced). Metal frames are elegant and often extremely thin, which can be decisive for the service life if the material is of poor quality.
• Nose pads are preferably made of silicone with sufficient softness and comfortable mobility. The temples should not put undue pressure on the temples.
• The index of the spectacle lens also plays a role. The higher it is, the smaller the thickness and curvature of the lens and the easier the selection of frames. A higher refractive index gives glass lenses. They are preferable for glasses with an optical power of more than 4 diopters. Low refractive index lenses are used in children's glasses and rimless frames.
• Coating spectacle lenses also important. Photochromic changes the ability to transmit light depending on the intensity of light. Anti-reflex clearing is useful for those who drive a car or work at a computer, as it reduces discomfort from reflected radiation. Hydrophobic prevents dust and dirt from accumulating on the lenses.

How does a doctor choose glasses?

An ophthalmologist is well aware of how to choose glasses for vision, and you should visit them before ordering them.

First, the center-to-center distance between the pupils is measured. To do this, use a millimeter ruler to measure the distance between the outer edge of the iris of the right eye and the inner edge of the iris of the left eye.

To select lenses, use a set of glasses and a visual acuity table. Lenses are selected separately for each eye. The patient is put on a special frame. The left eye is covered with a screen. A biconvex lens of 0.5 diopters is installed opposite the right one. Next, the lenses are changed step by step until the best vision is achieved. They prescribe the strongest glass with the best vision.

If vision does not clear up with convex lenses, use concave lenses, starting with 0.5 diopters with a gradual increase in glass power. The weakest concave glass with which there was clear vision is prescribed.

If glasses don’t suit you at all, and you want to forget about glasses and contacts forever, we recommend the M.S. Center. Norbekova.

Glasses can now be purchased anywhere, even on the train or at a clothing market, but with all the availability of such glasses, buying them “by eye” is an extremely dubious proposition. Even if you have a prescription from an ophthalmologist, it is impossible to ideally select glasses from a non-professional mobile ophthalmologist so that they correct your vision 100%. In order not to completely ruin your eyesight, before ordering glasses, you should definitely consult an ophthalmologist. Regardless of the cause of decreased vision, or, to select glasses, you need to go to a medical clinic or salon, where a specially trained optometrist will see you.

How to test visual acuity

Focusing only on subjective comfortable sensations, you cannot select glasses; before deciding to buy glasses, you must check your visual acuity. This is very easy to do with the help of an autorefractometer - a special device that is now even available in optical shops. With its help, a specialist can easily obtain basic information about the state of vision of a person.

It is worth noting that the information obtained from the results of autorefractometry is not enough to order glasses. Visual acuity is mandatory checked according to the table of signs, from a distance of 5 m. There are certain testing rules: the right eye is always checked first, while the left eye is covered with a special patch. The testing procedure is then repeated for the left eye. The essence of the method is to read letters in lines, starting from top to bottom. If the patient can read the last line in the table without errors, then his visual acuity is 100% and there is no need for correction. All other rows in the table reveal a discrepancy between visual acuity and the norm. For example, errors in reading the third line indicate that visual acuity is 0.3, the fourth - 0.4, and so on.

After the study has been carried out using the Sivtsev table, a trial frame with “minus” (divergent) or “plus” (collective) lenses is attached to the eye, in accordance with the data of the autorefractometer. If it is not possible to undergo autorefractomy, then weak diverging or collecting lenses will help determine visual acuity. They are placed on the trial frame one by one until the patient achieves maximum comfortable vision. If autorefractometry was not performed, by placing a weak plus and minus lens, find out in which case the vision improved, and subsequently take stronger lenses of this sign.

As the optical power of lenses increases, their degree of refraction also increases. One by one, the lenses are carefully tried on until the maximum visual acuity is achieved for one eye. For those who have difficulty distinguishing objects in the distance (with myopia), a lens with a minimum refractive power is selected, at which visual acuity is the best. In case of farsightedness, on the contrary, a lens with the highest value is selected, at which the patient sees equally well both in the distance and near. Both eyes are individually corrected to 0.7 - 0.8. After this, the visual acuity of both eyes is checked simultaneously, i.e. binocular vision is determined. If the lenses for each eye separately were selected correctly, then the sharpness binocular vision should correspond to 0.9 - 1.0.

The same indicators for each eye are not always determined, although they are more common than different indicators of visual acuity. In case of differences in readings, the permissible difference between the visual acuity of the right and left eyes should not exceed 2-3 diopters. To choose the most comfortable glasses, you need to walk around in them for a few minutes, read, this way you can check the portability of the selected glasses.

If it is not difficult to choose glasses for nearsightedness or farsightedness, then this type of visual impairment requires a more accurate and painstaking selection of spectacle lenses. For astigmatism, you need cylindrical lenses, which are quite difficult to get used to. If the patient is suffering high degree If you have astigmatism, then at first you will be prescribed glasses that are weaker than required, but after about two months you will definitely need to choose stronger glasses.

IN ophthalmological clinics, V diagnostic complex which includes a device called a phoropter, the lens selection process is much faster. If you have this attachment, a trial frame and a set of glasses are not required.

If glasses are selected for reading only, then a special table is used to test near vision. The scheme for selecting glasses according to the table for correcting farsightedness is no different from selecting lenses for distance. Similarly, each eye is checked separately, testing begins with the right eye, and when the diopters of the left eye are determined, testing of binocular vision continues. According to the patient’s needs, they are guided by the texts of tables from 4 to 6.

Vision problems can be so complex that both farsightedness and nearsightedness have to be corrected. In this case, you have to choose bifocal or progressive glasses. When calculating the optical power of these glasses, it is necessary to take into account the difference in diopters; for comfortable wearing, the optical power of individual zones should not exceed 2-3 diopters. It is important that for the selected indicators, visual acuity is sufficient.

Measuring the distance between the pupils

For 100% vision correction, the decisive factor is the correct fit of the glasses. To do this, the interpupillary distance is measured; in other words, the lenses in the glasses are centered. An experienced ophthalmologist can measure the distance between the center of the pupils using a very ordinary ruler, but now ophthalmologist's offices are often equipped with a special device designed to measure interpupillary distance - a pupillometer. It increases measurement efficiency several times. With any method of measuring interpupillary distance, it is important to remember that this indicator in distance glasses should be 2 mm greater than for glasses used for near reading. If these rules are not followed, incorrect alignment of glasses can cause not only visual discomfort, but also headaches, as well as decreased vision.

Prescription for glasses

The result of all measurements, selection of lenses and frames is a prescription for glasses, which takes everything into account individual characteristics points. This important document, which must be prescribed by a specialist optometrist or ophthalmologist, because the prescription includes many special points that are difficult for a non-professional to understand. The following items should not be omitted from your glasses prescription:

1. All data about the patient.

2. Optical power of spherical or cylindrical lenses, with the obligatory indication of the axes of the cylinder.

Examination and prescription

Faced with the need to purchase glasses for low vision, many wonder where to turn. If you want to wear high-quality glasses that will help you correct the lack of visual acuity, and not, on the contrary, aggravate the problem, you need to resort to the services of professionals. The quality of vision should be checked exclusively in a reputable optician or a private ophthalmology office equipped with modern diagnostic equipment. An experienced specialist will be able to carefully examine the condition of your eyes, and based on the research conducted, prescribe a reasonable and the right recipe for glasses. By contacting an optician with extensive experience and a good reputation, you can be sure that you will not only be given the right prescription, but will also be provided with full-fledged glasses selection services. Based on the condition of the eyes during the examination, the specialist will select a frame suitable for the shape of the face and offer modern lenses, and professionals will produce high-quality and durable glasses.

What are the consequences of neglecting the correct selection?

What happens if you don’t check your visual acuity at an optician or ophthalmology office, and buy completely unsuitable glasses in a random place? The answer is obvious - due to the fact that the process of addiction begins, you will cause significant damage to your vision. Failure to comply with optical parameters and wearing low-quality products is fraught with serious consequences. The body will try to compensate for the aberration, and as a result, a headache will occur, the eyes will become more tired, which will lead to deterioration of vision. For this reason, always have your eyes checked by a doctor before purchasing - this way you can keep your eyes healthy and reduce discomfort to nothing.

Selection of glasses

Having a prescription written by a specialist in your hands, it will be enough for you to simply choose glasses at the optician. But if for any reason you come without a prescription, you can have your vision tested at an optical shop if it has its own ophthalmologist.

It is strongly recommended not to purchase glasses from any non-certified points of sale. The goods sold in such retail outlets are priced an order of magnitude lower than in optical stores, but they definitely cannot be called high-quality. By making such a purchase, a person with poor vision can cause irreparable harm to the health of the eyes and only worsen the pathology.

When you go to an optician, you can always count on help from consultants in selecting and checking glasses. You may be offered ready-made glasses with lenses of the required diopter, or they may be made to order, based on the recommendations prescribed by the ophthalmologist. When choosing, you will also need to pay attention to the following parameters.

Lenses

Checking the quality of lenses in glasses is the most important parameter, because they are the main corrective element. Lenses High Quality at poor eyesight are selected depending on optical parameters. Parameters such as diopter value and center-to-center distance are determined by a specialist - if you have already had your eyes checked by an ophthalmologist in order to select glasses for your vision, you have probably been given this information.

An eyeglass store with good optics offers products with a high index of spectacle lenses. A parameter such as refractive index is the most important indicator lens class. Products with a high index have less weight, practically do not distort the eyes, and it is also easier to choose a thin and modern frame for them. Lenses whose refractive index tends to 1.6 are considered high-index.

Lens material

When you decide to buy glasses, you will need to decide what kind of lenses your glasses will have - plastic or glass. A number of advantages of glass lenses include:

• High scratch resistance.
• Possibility of applying special coatings to provide additional qualities.
• Affordable price.

Among the disadvantages, it is worth highlighting the fragility of glass products, the risk of injury and quite heavy weight. Glass lenses are not used for semi-framed models, as well as those that do not have a frame at all.

More modern material The material used in the production of lenses is plastic. Such lenses are comfortable, safe, they weigh much less than glass products, and also have increased resistance to chipping. This material is often used to make children's and sports models. But in terms of durability, they are inferior to glass ones, and can also crack in severe frost.

Frame

High quality optical stores offer their customers a huge selection of different frames. They can be metal or plastic and come in a wide variety of colors and designs. Undoubtedly, price policy will also differ, but it should be understood that high-quality optics for acute vision can't be too cheap. Choosing a frame, in addition to it appearance you should pay attention to:

• Strength - the main task of the frame is to ensure reliable fixation of the lenses. Therefore, it must be made of high-quality and durable materials that are not subject to deformation. The best choice would be titanium products; frames made from an alloy of non-ferrous metals are slightly worse in quality.
• Image - correctly selected glasses should hide flaws and emphasize natural advantages. A consultant will help you cope with this task and, using selection rules, will recommend a model that is right for you.
• Status - many opticians offer premium products that can emphasize the prestige of their owner and his high status. In such products, the quality has been tested by time, but at the same time it costs a lot.

Selecting high quality glasses should also include comfort. Pay attention to the mobility of the nose pads - if they are too rigid, this can cause pressure on the bridge of the nose and rapid fatigue. The best choice would be movable nose pads made of soft silicone. Check the quality of the optics by examining the size of the temples. It is important that they do not put pressure on the temples and behind the ear area. An indicator of a correctly selected frame is the absence discomfort even with prolonged wear.

Coating

After you have checked the quality of your glasses frames and lenses, you can move on to such an important parameter as coating. In some models the lenses are covered special composition, which adds certain properties to them, such as:

• Increased strength.
• Scratch protection.
• Resistance to moisture and dirt and others.

Many of those who decide to have their vision checked at an optics salon and purchase glasses opt for models with anti-reflective (anti-reflex) coating. The applied composition increases the degree of transparency of the lenses, and also significantly reduces the level of reflection of light rays from their surface. The most popular today is modern multilayer coating. Its peculiarity lies in the fact that it combines all the above properties.

Conclusion

The set of parameters that we examined above is the answer to the question “How to check the quality of vision glasses.” By contacting an optician with a good reputation and many clients, you can be sure that you will be served by professionals and will offer not only exceptional quality products, but also high level service. It is worth noting that many opticians issue a warranty on frames and lenses, which indicates the seriousness of the company and care for customers.

Selecting this indispensable Everyday life for many an accessory, do not skimp on the examination and quality of the product. This is the only way to keep your eyes healthy for many years.

If a person has a problem that is accompanied by a decrease in the acuity of visual perception, he makes a visit to an ophthalmologist. It helps to choose a therapy method that will eliminate visual dysfunction.

Sometimes, the correct one is a good alternative to a surgical technique. In addition, choosing glasses takes a short time, and the result of improving visible objects appears instantly.

It should also be taken into account that glasses should not only correct vision, their shape should be aesthetic, and be combined with the parameters of the face, complementing the lifestyle.

Selection of glasses for vision and its features

When choosing glasses for vision, their shape, workmanship, and scope of application are taken into account. In everyday life, glasses must combine the frame configuration and lens thickness.

For active image life, if a person plays sports or drives a vehicle, they must be reliable and safe.

To choose the right glasses for your vision, you must adhere to the following rules:

Visual acuity testing and lens selection

When choosing glasses, it is best to contact medical institution, and visit an ophthalmologist, especially if the patient is visiting for the first time. Do not allow independent selection, which is carried out at random, without establishing the causes of visual impairment.

Stages of vision testing and lens selection:

Professional glasses are created specifically for people who want to protect their eyesight from screen radiation as much as possible. They block ultraviolet radiation, the eyes do not hurt, there is no pain or tearing.

I recommend it, because these glasses will help you almost completely relieve eye strain while working at the computer, reading, watching movies on TV and the phone, and also increase the receptivity of information.

Optical lenses and their choice

Most people, when choosing glasses, pay special attention to the frames. They believe that good design will highlight their style and personality.

This is partly correct, but we should not forget that glasses, first of all, are optical device, and are intended to eliminate vision pathology.

To implement right choice the following criteria must be followed:

Types of glass

There are three types of glasses for glasses:

1. Bifocal. A distinctive feature is that one lens combines two at once. Bottom part glass is designed for visual work at close range (reading a book, knitting). The entire remaining area of ​​the glass makes it possible to view objects located in the distance.
2. Multifocal. This is one of the latest developments in ophthalmology. Such optical glasses make it possible to carry out the visual process at different distances; in addition, they are well suited for the occurrence of age-related myopia.
3. Afocal. This type of lens is used in frames for glasses with sun protection, or for working at a computer monitor. Such glasses have no optical properties.

Material

Depending on the purpose of the glasses, it is taken into account what material they are made of.

Glass

Glass has many positive qualities:

The disadvantages of this material include:

• Compared to the plastic version, they are heavy. When worn constantly, they press on the bridge of the nose and leave a mark.
• Highly fragile, may break or burst if dropped. Requires careful handling.
• If the patient is diagnosed with astigmatism, diopter lenses have a high price due to the labor-intensive process of their production.
• Photochromic glass yellow or gray have reduced adaptation to lighting conditions. This may occur if a person moves from a light room to a dark room. Difficulty visual process can last up to 20 seconds.

Plastic optics (polycarbonate)

They have a number of advantages compared to glass analogues:

Design

Depending on the design, glasses can be:

• Spherical. They have a massive thick shape, which is why their weight is increased. The image of a clear picture is located in the center, distortion is observed closer to the periphery. When choosing them, one should take into account the fact that they can distort the appearance of the visual organs.
• Aspherical. Such lenses have refined shapes, and their weight is half that of the previous version. They have the shape of an ellipse. The main advantages of the aspherical shape are:
  • The image of visible objects occurs with minimal distortion.
  • They have a wide angle of clear vision.
  • The peripheral zone does not produce distortion.
  • Does not change the shape of the eyeball.
• Lenticular lenses. Have distinctive feature, since only the central part has optical properties

Coating

This is an important quality when choosing glasses.

When ordering lenses, you can choose the following types of coatings:

• Sun protection. Have a large selection color range, prevent bright sunlight from entering your eyes.
• Strengthening. Increases the ability to protect glasses from minor damage and scratches.
• Water repellent. When dirty, they are well cleaned from dust, dirt, and water drops.
• Protective. Used when working at a computer monitor, they prevent the development of eye fatigue, which can occur due to exposure to radiation emanating from the screen.
• Mirrored. Gives the patient an aesthetic appearance.
• Anti-glare. Capable of reducing the amount of reflected light.
• Multifunctional. They have a number of advantages.

Color

Lens coloring can give glasses a stylish design and make them a fashion accessory. However, it does not affect the optical characteristics.

In some cases, a variety of colors has a therapeutic effect(color therapy):

How do different diopter levels affect the choice?

When choosing glasses for vision, very often a situation arises when the level of visual acuity has a different indicator (more in one eye, less in the other).

To implement correct selection glasses, use a trial frame with changing lenses.

This procedure is carried out in stages:

If there is a slight difference, it is allowed to wear glasses with the same optical lenses. If a large discrepancy in diopters is detected, glasses are prescribed that are not commercially available, since they are made to order in optical stores. It is important to consider that the difference in diopters should not exceed 3 units.

If such a pathology is detected, the patient may be prescribed additional methods research, since sometimes different indicators of visual acuity can be the cause of:

• Lens disease.
• or .
• Diseases that change blood circulation inside the eyeball.

Selection of glasses for vision based on face types

The selection of glasses is carried out taking into account physiological characteristics facial configurations. This takes into account the location and shape of the chin, nose, forehead, hair length, or hair growth line.

Distinguish following forms faces:

1. Triangular. With this type, there is a narrowing of the facial area towards the chin. This shape involves wearing round, triangular or square shape. If the frame has patterns, it may give the impression that top part the facial area looks wider.
2. Round. To achieve complete harmony between glasses and a rounded face shape, you need to use frames of the correct geometric shape (square, rectangular) or try on a model “ cat eye" The correct choice would be to choose a large frame.
3. Oval-shaped face(slight difference between the forehead, cheeks and chin), does not require compliance with geometric parameters when choosing a frame. Special attention should be applied to models with thin frames. Massive frames can enhance oval facial features.
4. Square. With this face shape, a massive chin stands out, and the contours of the face are pointed. For this type, glasses frames that resemble a “cat’s eye” or a square shape are best suited.

Stories from our readers!
“I spend 12 hours every day at the computer and it’s not surprising that my eyesight began to deteriorate from this. I had to buy glasses. I chose this model and did not regret it. I really began to see everything better and more clearly in them.

I use these glasses while working on the computer, reading books and watching movies. I recommend it to anyone who needs to sit in front of a monitor for a long time."

Types of glasses frames

When choosing glasses, it is important to pay attention to:

• Constructions. Depending on the type of lens mount, the frame can be:
  • Obodkova.
  • Half-rimmed.
  • WITH complete absence rim. If the patient has chosen a design without a rim, he should know that such a model looks transparent on the face. Rim models are considered bright and noticeable.
• The material used mainly affects the durability of the frame and its weight. Nowadays, glasses frames are quite common, which are made using:
  • Plastic
  • Polycarbonate (a type of plastic).
  • Tree.
  • Combinations of metal alloys.
• The size of glasses does not affect the function of the visual organs:
  • Massive glasses always give a person a serious look, and his facial features visually acquire increased size.
  • Thin, neat frames are well suited to the female population. Due to their elegant shape, they look good, and during prolonged communication they become invisible.

Glasses for farsightedness

With the development of this pathology, glasses with a plus value are most often prescribed.

If this type of corrective therapy is not used, then over time the patient will lose the ability to clearly image objects at close range.

To correct the criteria for visual perception and increase its sharpness, the following is prescribed:

When selecting glasses for vision, the ophthalmologist is guided by the following rules:

• The patient’s professional activity must be taken into account. If his work involves performing precise manipulations, illuminated vision glasses may be used.
• It is not allowed for the glass to be located more than 12 mm from the eyes.
• Use only glass with a positive value.
• Glasses should be worn comfortably without causing discomfort.

Glasses for myopia

In the event that the ophthalmologist diagnoses the patient (the person has difficulty viewing distant objects), corrective glasses are prescribed.

To do this, follow the rules for correct selection:

The selection of glasses is carried out gradually. First, diverging lenses with a minimum value are inserted into the trial frame, followed by their increase.

This procedure is performed until visual acuity reaches its maximum peak:

• If myopia progresses rapidly and has severe form It is best to give preference to wide glasses for a secure fit.
• When the diopter value is low, a semi-rimmed or rimless form is used.
• To far away, optical glasses with a negative value are used. But when working at close range, you need to remove them and put on a second pair of glasses to view objects at close range.
• In some cases, plus lenses are used to treat myopia in children. They activate the natural forces of the body and eliminate the eyes.

Problems with choosing the wrong glasses

If the choice of glasses was made independently, without consulting a specialist, this can affect not only the condition of the visual organs, but also the body as a whole.

Therefore, in almost every optical salon you can undergo a free diagnosis of your vision organs and choose and order the right glasses.

Most often, the patient may experience:

If such symptoms occur, you should urgently visit an ophthalmologist and have your visual acuity checked again. Sometimes the above clinical manifestations are temporary and disappear within 10 days after the visual organs adapt to a new vision of the environment.

Interpupillary distance measurement

To establish proper lens alignment, you need to measure the distance between your pupils. Usually a ruler or device is used for this purpose. pupillometer.

Manipulation using a ruler is carried out by applying it to the bridge of the nose. The zero mark of the measuring device is located at the level of the outer limb of the right eye, and the end mark is the inner limb of the left eye.

The error of this technique is no more than 1 mm.

Prices for vision glasses

The price for this type of product may vary from 150 rubles and higher.

The cost of finished glasses will be related to:

• With the region of Russia.
• Using glasses frame material.
• With lens technology.
• Depending on whether adult or children's glasses.
• You can pay a lower price by ordering goods online through online stores and having them delivered to your home.

Conclusion

Selection of glasses for vision is very important stage, to eliminate visual pathology. The right choice can only be made after consulting an ophthalmologist.

He will produce everything necessary manipulations, which will allow you to accurately determine the acuity of visual perception, and make an individual selection of glasses, taking into account their shape and the quality of the material.

It is important to remember that only the right choice of glasses can stop the progression of the disease. When purchasing glasses outside an optical salon (on the market) there is Great chance that wearing them will be accompanied by a feeling of discomfort, eye fatigue and headaches.

If you have problems clearly seeing objects in the distance, cannot distinguish letters when reading at the usual distance, or get very tired when working in an office, then you need to check your visual acuity and choose glasses or replace the ones you use.

Where to check

How to prepare

Before the visual acuity test begins, your eye doctor or optometrist will talk with you and ask questions to learn about you, your eyes, and your overall health. Be prepared to talk about common diseases, hereditary eye diseases, special risk factors of professional activity, medications taken, allergies.
Remember that some medications may affect vision, causing short-term or long-term side effects. Thus, non-steroidal anti-inflammatory drugs, antiarrhythmic drugs, antidepressants, neuroleptic drugs, calcium channel blockers, oral contraceptives, tranquilizers, psoriasis drugs, tetracycline, thiazide diuretics and some others help increase the photosensitivity of the organ of vision. A number of drugs sometimes cause changes in pupil size by affecting the light sensitivity of the eye - these are atropine and other anticholinergics, scopolamine, antibiotics (fluoroquinols and tetracyclines), anticonvulsants (phenytoin), antidepressants (selective serotonin reuptake inhibitors), antihistamines, central nervous system stimulants (amphetamines, cocaine), sedatives (benzodiazepines), drugs that prevent erectile dysfunction, phenothiazines.

Visual acuity test

Refractive Study

If autorefractometry has not been carried out, then, by attaching weak plus and minus lenses, they find out in which case the vision has improved, and then select lenses of the appropriate sign. lenses Successively try lenses of increasing optical power until the maximum visual acuity for the eye is achieved. For myopia, a lens with minimal refractive power is prescribed, providing high visual acuity. With farsightedness, on the contrary, with maximum refractive power, at which visual acuity is the highest.
Then a visual acuity test is performed binocularly, that is, both eyes together. In this case, the visual acuity of each eye should be 0.9-1.0. And if the quality of vision is different, then the maximum permissible difference in the optical power of the prescribed lenses should be no more than 2-3 diopters, depending on the patient’s individual tolerance.
Identification of the type and degree of astigmatism consists in determining the spherical and astigmatic components of the correction, as well as the position of the axis of the astigmatic lens, which ensures maximum visual acuity. To determine astigmatism, so-called astigmatic figures are often used, and when using optotypes, crossed cylinders are used.

The research method is based on uneven vision astigmatic eye lines of different orientations in astigmatic figures, or, as they are sometimes called, dials. These figures are used both to identify astigmatism and to determine its degree and the position of the main sections. Crossed cylinders are mainly used for final stage refraction studies to clarify the degree of astigmatism and the position of its main sections, that is, the strength and direction of the axis of the correcting cylinder.
After installing the lenses in the trial frame, the patient should be allowed to stay in the trial frame for several minutes, read, and walk around to check the tolerance of the corrective lenses. The parameters of these lenses are indicated in the prescription for glasses or contact lenses.
Interpupillary distance measurement carried out after selecting the correction using a set of trial lenses or a phoropter. Usually the distance between the centers of the pupils is measured using a regular ruler or a special device - a pupilometer. In well-equipped ophthalmological offices, special electronic measuring systems are used that allow all the necessary lens centering parameters to be established with high accuracy. Incorrectly measured interpupillary distance will result in incorrect centering of the lenses in the frame, which in turn can cause feeling unwell with visual stress. The prescription indicates the interpupillary distance for both eyes, and if it is necessary to prescribe progressive or aspheric lenses, the monocular pupillary distance.

Other methods for studying refraction

The subject is shown a luminous display, the left half of which is colored green, and the right half is colored red. Both have symmetrical black optotypes. The subject with a selected lens is asked to indicate against which background the signs seem clearer or blacker to him: red or green.
If it is red, then the eye alignment is myopic and a negative lens of greater optical power should be installed in front of the eye, and a positive lens of lower optical power; if it is on a green background, then the eye setting is hypermetropic and you need to choose a weaker negative lens, and, on the contrary, a stronger positive lens.

Binocular vision study

Glasses prescription

All prescriptions written out should be saved, since if necessary, they can be used to determine how vision has changed over time.

The selection of glasses should be carried out by a qualified specialist. Incorrectly chosen glasses can cause constant eye fatigue, cause headaches, fatigue, malfunction.

Prepared by Olga Shcherbakova