Lens diameter 14.2 can we wear 14.0. How to determine and choose the size of contact lenses for your eyes

Huge, wide-open eyes are a constant feature of fairy princesses. How often in childhood we wanted to be like them ... Fortunately, the modern beauty industry allows you to make your eyes visually larger, and not only with the help of plastic surgeries or makeup. The latest trend that came to us from Korea is lenses that increase the eyes.

In which lenses do the eyes appear larger?

There are several basic types of lenses: clear, tinted, colored, carnival and colored magnifying. Of course, you will need the latter. They are easy to distinguish from ordinary colored lenses, because magnifiers are always much larger than the natural size of the iris. They can be monochromatic, repeat a natural pattern, or create unusual effects. Correctly selected lenses can completely cover even brown eyes.

When choosing, you need to focus on the diameter of the lens, because the effect of magnification and the perception of the eyes by others depends on it to a greater extent.

Often, manufacturers indicate not only the diameter of the lens, but also the so-called "magnification effect". For example, with a diameter of 14.5 mm, the magnification effect can be 17.8 mm. This is just an approximate result of the perception of the eyes by others.

Basically, manufacturers produce lenses with a diameter of 14-15 mm, which are suitable for most situations.

What else to look for?

Take your time to make a decision, because the comfort of wearing and the life of lenses does not depend only on their size.

1. . It does not coincide with the curvature of the cornea, but depends on it. For Europeans, models with a radius of curvature of 8.6 are most often suitable; for people with a narrow cut of the eyes, it is better to choose a radius of 8.4.
2. Oxygen permeability. It depends on it how long you can wear lenses without interruption. With a parameter of 80 Dk / t in, you can spend 8 hours daily in lenses. 130-140 Dk / t allows you to wear them without taking off for several days.
3. Moisture content. Lenses with a low water content (up to 50%) last longer, are durable and are great for correcting small deficiencies. Magnifying lenses also often have a moisture content of 38-42%.
4. Material. Hydrogels are cheaper, in them oxygen permeability directly depends on the water content in the lens. Silicone hydrogels allow you not to think about moisture content and wear well all day, but they are more expensive.

Do not forget to read these parameters on the packaging or the manufacturer's website, because lens care and wearing comfort depend on them. And use eye drops if you are in a dry room or feel discomfortt, a wet shine will give the look even more expressiveness.

How to choose a manufacturer?

Today most eye lenses are made in South Korea, but some are imported from other countries.

Benefits of magnifying lenses

1. Most modern models allow you to see well even in semi-darkness, because they do not block the pupil.
2. Allows you to make even dark eyes light or completely change their color.
3. Eyes are visually enlarged.
4. The wide range helps to create a spectacular daytime makeup or doll look.
5. There are corrective vision for myopia model.
6. Good quality.

disadvantages

1. Some models look unnatural.
2. They require careful selection for the color type and facial features.
3. Individual intolerance is possible.
4. May not be suitable for people with or accustomed to lenses for continuous wear.

Enlarging your eyes is easier than ever today. Do you want a vivid doll image? Please contact Korean manufacturers. Maximum naturalness? Your lenses are made in the West. The main thing is to choose those models that you like, then those around you will be delighted.

Comfort, as well as the duration of wearing lenses very often depends not so much on the level of production as on the correct selection of products. Unfortunately, today only a few consumers know how to determine the ideal soft optics for themselves correctly and mistakenly rely only on diopters. In fact, the correct selection of lenses includes many other parameters that affect the comfort of use. What these parameters are and how to choose lenses for the eyes according to them according to the recommendations of doctors will be discussed in this material.

Selection methods

Currently, the selection of soft lenses is carried out taking into account several features of the patient's eye, including:

• Corneal radius;
• Sagittal depth (a parameter that depends on the sagittal (geometric) axis of the eye, which varies depending on the presence of certain pathologies, for example, it is less in the myopic eye);
• Chord diameter.

It is very difficult to measure these parameters for each eye, therefore the selection is carried out according to the typical closest value. The basic formula for sagittal lens fitting in this case is as follows:

For this formula:

• D is the chord diameter;
• R is the radius of curvature of the lens;
• A is the value of the sagittal size.

This selection technique is used by almost all ophthalmologists, regardless of which manufacturer's optics they use. To simplify the selection of lenses according to this technique, special tables are used. This technique is applicable to both soft and rigid lenses and is universal for patients with various pathologies, including myopia, hyperopia, or astigmatism. The procedure for selecting optics according to such tables will be discussed below.

On measuring the diameter of the cornea

This technique was originally proposed by the company engaged in the production of lenses "Bausch & Lomb", in which ophthalmologists were asked to select the optics for patients according to the table, focusing on the following patterns:

• Lens diameter 12, 5 is recommended when the corneal diameter is less than 11.5 (which corresponds to the models of the U, F series, the proportion of patients suffering from myopia and N, H3 - for hyperopia);
• Lens diameter 13.5 is recommended for corneal diameter 11.5-12.0 (corresponds to the series for hyperopia B3, H3 or O3, U4 for myopia);
• 14.5 - the diameter of optics, assigned when the diameter of the cornea is over 12.0. Lenses of the B4, H4, O4, U4 series are suitable for it;
• If the patient has a large palpebral fissure, it is recommended to select larger specimens;
• In the presence of a steep cornea of \u200b\u200b45.0 D, it is recommended to take lenses of a smaller diameter.

Read where to cure optic atrophy.

Below is the table itself for choosing a lens based on the diameter:

This method is applicable for both patients with farsightedness and myopia. It makes it possible to select the most suitable suitable samples, but in some cases it allows the production of special models on request.

Read also about contact lens addiction in detail.

On measuring the radius of the cornea

This method is widely used primarily by the Cooper Vision enterprise and is based on the following laws:

• When choosing optics, both the diameter and radius of the cornea are taken into account;
• They are also guided by the mobility of the lens - in terms of choosing a more convex or flat analog;
• Take into account the level of moisture in the eye;
• The size of the palpebral fissure is taken into account - the larger it is, the larger the lens diameter should be.

With this method, it is necessary that the lens is 1 or 1.5 mm in diameter behind the limb. This provides the most complete coverage of the angle of view and gives the user maximum comfort while wearing the products.

Measuring the sagittal depth

This method uses the study of clinical refraction of the eye to obtain the most accurate parameters for fitting the lens. It is applicable to work with Softcon optics. The choice of lenses in this technique is also based on the following laws:

• Lenses at 8.4 / 14.0 are recommended for patients with corneal radii of 41.25-42.0;
• Lenses for 8.1 / 14.0 or 8.4 / 14.5 for a corneal diameter 44.5-45;
• For a more accurate selection of samples, it is recommended to use the manufacturer's tables for typical optics.

Since all of the above methods are focused on working with a typical set of lenses, they are not always productive for every patient. That is why doctors, when choosing soft optics, are also guided by the thickness of the lens.

Read about how to choose contact lenses online in.

Lens thickness

The focus on this parameter should take into account not only medical indicators, but also the patient's convenience when working with thin optics samples. When choosing a lens by thickness, they are guided by the following indicators:

• Compliance with the anatomical features of the eye;
• Sample tolerance level;
• The level of tearing of the eye: with a low rate, it is recommended to use a standard thickness of products, since ultra-thin analogs can dry out the mucous membrane;
• The presence of thickening of the iris, for example, after injuries and operations: in the presence of this feature, the use of a lens of greater thickness is required.

Read more about multifocal lenses in.

Trial soft lens set

It is far from always possible to choose lenses the first time, even taking into account all the details. In many cases it is advisable to use a trial soft lens set. These are produced by all manufacturers of soft optics today. Tables guide the specialist in choosing according to such parameters:

• Type of pathology (myopia, karatoconus, aphakia);
• Center lens thickness;
• Lens refraction;
• Radius as well as the width of the sliding zone;
• The radius of curvature of the rear optical surface.

The table itself for the selection of trial soft lenses:

These tables provide the fastest possible selection of lenses from the set. They try on products from such sets as follows: the patient is put on lenses one by one, they wait up to half an hour from the moment of trying on, until the lacrimation calms down and the inflammation of the eye decreases, and after that they observe the nature of the lens fit, its mobility, as well as the appearance of uncomfortable sensations while wearing it ...

Sometimes the structural features of the eye area do not allow choosing a standard lens for it. In the event that none of the standard forms is suitable for the client, it is recommended to manufacture lenses according to individual parameters.

Read about the rules for wearing contact lenses.

Lens position in the eye

In some cases, a lens matched to certain parameters is incorrectly positioned in the eye. To resolve issues related to similar problems, there is a special table that gives a list of universal recommendations for such problems:

They should be guided in the case when there is a need to quickly select the most adequate analogue for comfortable wearing of optics by the patient.

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conclusions

As you can see, the selection of lenses that are comfortable in constant wear is a rather difficult and painstaking task. It is almost impossible to carry it out without the help of specialists. However, if you go through all the necessary studies, carefully consider the recommendations of the ophthalmologist, you can choose high-quality and comfortable products to wear. With the wrong selection, you can harm yourself up to the development of dangerous diseases (for example, cataracts). may be ineffectual.

You can choose the right contact optics only at an appointment with an ophthalmologist.

The doctor will check visual acuity with and without correction, carry out refractometry, ophthalmometry, ophthalmoscopy, biomicroscopy.

Determine yourself required parameters impossible.

What are the parameters for determining the size of contact lenses?

The size of the contact optics determines two parameters: radius of curvature and diameter contact lenses, which are indicated on the package. They are measured using a special device - an autorefractometer.

Comfort depends on the first indicator when worn as well as eye health. Basically, the radius of curvature characterizes the bend of the outer surface.

And the diameter depends on the size of the corneaand serves as a measure for determining the volume of the sphere, is responsible for the natural look and ease of use. When selecting optics, the following error occurs. Subjectivelythe patient finds that a tighter fit is more comfortable than a loose fit. On practice it is worth finding a middle ground so that there are no complications.

The lens is believed to be out of size, if itching, burning and redness appears eye. At the same time, factors that cause such symptoms are always excluded: damage, expired shelf life, non-compliance with hygiene rules.

Important! A common cause of these symptoms is individual reaction to the material.

Both require visit a doctorin order to find out the reason.

Lens radius of curvature: what is it?

This parameter characterizes the concavity of the inner surface... It can be standard and enlarged. The base size is the value from 8.3-8.7 mm. Suitable for most people with a normal corneal structure.

Oversized radius sometimes exceeds 9.0 mm. The most convex product has a smaller radius. This fact causes correct landing.

To ensure comfort without visual distortion, the shape of the eyeball (cornea) and the curvature of the lens must follow each other's contours. If the shell is more rounded compared to the cornea (the circumference of the lens is smaller), the fit will be steep. This leads to excessive vascular tension and redness of the eyes.

If the membrane has flatter characteristics (lens circumference is larger), contact optics become movable and the fit is flat. This causes constant friction, which leads to corneal inflammation and swelling. The very procedure for determining the radius of curvature takes two minutes. It is carried out using computer technology and is painless.

How to find out the size of the cornea

Represents diameter of the cornea or convex transparent part eyeball. It looks like a convex-concave aspherical lens. The vertical dimension of the cornea is smaller than the horizontal one.

Photo 1. Indication of the location of the cornea of \u200b\u200bthe eye and its internal structure, consisting of several layers.

The diameter is also different and is about 10.00-10.56 mm. An adult has a size horizontally characterized by the value 11.8 mm, vertical - 11 mm.Wherein radius of curvature normally does not exceed 7.8 mm... It also has a certain convexity coefficient.

What does the lens diameter affect?

The location of the lens on the eyeball is established by the diameter of the cornea. Selectioncorrection means carried out according to a special table, which has a pattern: the diameter of the cornea always less lens diameter by 1.00-1.50 mm. This feature provides convenience and comfort. When decentering the sphere, a larger diameter is selected. If immobility is observed, it is reduced, with excessive displacements, it is increased. This helps relieve eye strain.

Is the curvature of the product greater than the curvature of the cornea?

This parameter is considered an individual valuefor every person. It depends on the characteristics and shape of the cornea.

As correction meanseyes are put on the cornea, they must completely correspond to the natural form.With standard indicators of corneal curvature the required radius is considered to be r \u003d 8.6 mm.

Among the products of world brands you can find the best option for every person... In case of non-standard vision parameters, they contact the manufacturers personally.

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Effect of material on lens fit

In addition to the basic parameters of the lens size, the quality of fit is influenced and the material from which the contact optics are made.

Important! Correct fit determined only by a doctor... As a result of self-selection, there are frequent cases of hypoxia, which leads to infectious diseases and keratitis.

Each composition, hydrogel or silicone hydrogel, has a different fit with the same curvature. Hydrogel lenses are poured out of a low moisture gel. With the loss of the water component, the dimensions of the contact optics themselves change, and the fit on the cornea becomes tighter.

For convenience, developed biocompatible technologies, the main advantage of which is the components, similar in composition to the natural tear film... They prevent excess evaporation.

Silicone hydrogel breathable... The material contains siloxane, which has higher air permeability coefficients. Despite the better fit compared to hydrogel, need additional moisture for maximum comfort.

A test is carried out to determine the correct fit. To do this, the lens is shifted up the cornea. If it freely returns to the central position, it means that it fits the curvature parameters. Normally, the mobility is 1.5 mm.This is necessary to provide the eye with a natural tear.

Standard sizes of contact lenses for eyes

To purchase contact lenses, it is not enough to know only the diopter value for both eyes. Diameter is sometimes different for the left and right organs of vision. And the base curvature is responsible for the quality of the fit and does not differ.

Standard parameters:

1. Diameter DIA \u003d 13.5-14.5 mm in 0.1 increments.
2. Radius of curvature BC \u003d 8.3-8.7 mm in 0.1 increments.

The main difficulty in selecting the size of contact optics is limited production according to the required parameters... Often, brands are not suitable for one of the measurements.

In any case, among a wide variety of products choose the right one, neglecting the advantages of moisture protection or breathability, which affects the wearing mode. This is especially true for people with an unusual structure of the eyeball.

How to find out and choose the right size of contact lenses that are suitable for your eyes? What is the diameter and radius of the base curvature of a contact lens? Should contact lenses be the same size as the cornea of \u200b\u200bthe eye?

In this article, we will look at an important and frequently asked question that concerns the correct selection of the size of a contact lens, determining the correct parameters.

Determining the size of a contact lens

If the lens diameter is incorrect

If the diameter of the lens is not correctly selected, then the fit of the lens will be either free, if the diameter is too large, then the lens will be excessively mobile and this will lead to discomfort. The fit will be tight if the diameter is small - in this case, the edges of the lens will be in the limbus zone, which will lead to a violation of the blood supply to the cornea.

Contact lens size and corneal size do not need to match

When developing the design and size of a contact lens, the size of the "universal" cornea of \u200b\u200bthe eyes is calculated on which this contact lens will fit perfectly. When calculating the parameters of the "universal" cornea, the size of a huge number of corneas is taken into account from which the arithmetic mean value is calculated.

This is why a one size fits all contact lens will fit most people. And only because of this, manufacturers do not produce contact lenses individually for each size of the cornea of \u200b\u200bthe eye.

Some manufacturers, in addition to the standard lens size, specifically produce lenses for non-standard corneal sizes. But such corneas are the exception rather than the rule.

Determining Lens Size Using Acuvue Lenses as an Example

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Inna 02/17/20

Hello! When checked, they said that a flat cornea and lenses are needed for 10.3, but such are not available. Is it possible to fix the situation somehow? Do the exercises? Drops? Previously, I could safely wear lenses, but now only for a radius of 9 and then no more than 2 hours, otherwise my eyes hurt a lot

Natalia Gusakova 08.11.19

Anastasia, hello! The choice of the size of the base curvature of the lens is possible only when evaluating the fit of the lens on the cornea, lenses of different materials and designs can fit completely differently even with similar dimensions. Therefore, the choice of the size of the lenses is possible only in the office of contact correction.

Anastasia 07/30/19

Hello. Tell me please. I wear daily lenses with a diameter of 14.3 and a radius of 8.5. I want to upgrade to biweekly, what diameter do I need?

Natalia Gusakova 22.07.19

Hello, Alexander. The main criterion for choosing lenses is. Lenses of the same parameters but different manufacturers will fit differently. The correct fit can only be selected by an ophthalmologist or optometrist in an optician's salon.

Natalia Gusakova 22.07.19

Hello Igor. Standard lenses with a 7.5 radius of curvature are not available. The only possibility is custom-made Konkor lenses, we do not cooperate with this company.

Igor 04/30/19

Hello. Tell me the possibility of purchasing cont lenses: +11 diopters curvature 7.5

Alexander 03/30/19

Hello, I am currently using lenses 1day acuvue trueye 8.5, 14.2 Will soflens daily disposable 8.6, 14.2 fit?

Natalia Gusakova 16.03.19

Karina, hello. To properly fit toric lenses, it is necessary to evaluate the fit of the lens to the cornea. The main criterion for correct fitting is good fit of the lens on the cornea of \u200b\u200bthe eye.

Karina 03/02/19

Hello. I have astigmatism, it is difficult to choose lenses. According to the data, the radius of curvature is 8.6, the diameter is 14.5 large. And then you can't choose. All presented toric (astigmatic) lenses with a diameter of 14.5 What to do?

Natalia Gusakova 26.11.18

Olga, hello! The selection of colored lenses is carried out according to the same parameters as for conventional lenses.

Olya 11/24/18

Hello. Do you need all this for colored lenses?

Natalia Gusakova 23.04.18

Alexey, hello! The main indicator of correctly fitted contact lenses is their fit on the cornea. The size of the lenses you have previously used is not a standard when choosing lenses of different designs and materials.

Alexey 04/23/18

Good day. I have worn from the moment I bought my first pair of 55uv ophthalmix lenses, 8.6 radius, 14.2 and -4.25 diopters in diameter. Now these lenses have been discontinued. As can be seen from the above text, it is impossible to change the diameter of the lenses up or down. Will you have to select from the available ones or can you vary slightly by 0.1-0.2 mm?

Natalia Gusakova 18.03.18

Elena, hello! The diopters in contact lenses and diopters corresponding to your visual acuity in spectacle correction differ due to the presence of the vertex distance (see the article "Vertex distance"). Therefore, diopters of -12.0 in contact lenses correspond to diopters of -14.0 with spectacle correction.

Elenka 03/18/18

Hello, my glasses are -15.0 and lenses are -12.0 Acuvue Oasys. Should I increase the diopter of the lenses? If yes, how much to feel comfortable? Thank you.

Natalia Gusakova 12.03.18

Love, hello! It is not correct to advise contact lenses according to the data of a refractometer. The main indicator of correctly selected contact lenses is their correct one.

Love 03/10/18

Hello! Please tell me what lenses can fit? Weak small-sweeping nystagmus (it is almost imperceptible) Autorefractometer data: R 8.02 / 8.03, D 42.5 / 43.0

Alla 01/27/18

Good day. The husband has -15.0; radius of curvature according to the autorefractometer OD 7.29 / 7.25 OS 7.3 / 7.25. We can’t pick up contact lenses for him. We tried lenses from different manufacturers. lenses with standard parameters are not comfortable for him. Maybe this is due to its small radius? According to the autorefractometer data, tell me what radius you recommend to him: 8.0; 8.2 or 8.4? Thank you in advance.

Natalia Gusakova 10.01.18

Victoria, hello! Besides diameter, there are many other parameters that affect the fit of contact lenses, such as lens material, base curvature, edge design. Different lenses have completely different parameters, but this does not mean at all that they will not suit you. Likewise, it does not mean that other lenses with the same parameters as your previous lenses will definitely suit you. Therefore, the main criterion for correctly selected soft contact lenses is.

Victoria 08.01.18

Hello! Tell me please! I used to take clarity 8.8 minus 3.25 lenses and a diameter of 14.1, but now I can't find a diameter of 14.2 or 14.5, tell me the diameter plays a role in the lenses? Thanks in advance !!!

Natalia Gusakova 15.12.17

Venus, hello! The principle of choosing colored contact lenses is the same as for conventional lenses. If you take ordinary lenses -5.25, then you need to take colored lenses with the same diopters. But colored lenses with such diopter values \u200b\u200bare only available from Alcon. By the way, these are safe silicone hydrogel lenses, unlike other colored lenses that are hydrogel.

As for the size of lenses, the only criterion for correctly choosing the size of any lenses is their correct fit on the cornea of \u200b\u200bthe eye and in no case is the size of previous lenses a criterion, since lenses from different manufacturers or even different lenses from the same manufacturer will have different designs, consist of different materials, therefore, if some lenses have a base curvature of 8.4 and suit you well, then other lenses with other parameters will also fit well on the cornea with a size of 8.6 and a diameter of 14.2.

Therefore, the selection of lenses or the transition to lenses of a different design must be carried out in the doctor's office, who will be able to assess the correct fit of the lens on the cornea, this will be the criterion for the correctly selected lens size. The only thing to consider when purchasing colored lenses is the possibility of the appearance of a feeling of "fog" in the lenses due to the narrowing of peripheral vision due to the pattern of colored lenses.

Venus 12/15/17

Good day! My daughter wears lenses with a radius of curvature of 8.4 and a diameter of 14.0 minus 5.25. But she really wants colored lenses, but with a radius there is only infinity (Korea), we do not want them, tk. there the lens is completely colored, and therefore distorts color perception. Could you tell me: 1) do colored lenses have a difference than colorless ones (different radius and diameter) ?; 2) if -5.25, then it is necessary with colored lenses at - 5.50. Thank you!

Natalia Gusakova 23.11.17

Daria, hello!

Acuvue 1 day TruEye and Acuvue Oasys lenses have different designs. The TruEye standard is 8.5 and the Oasys is 8.4. Therefore, TruEye lens fitting always starts with a base curvature size of 8.5, and only if they fit snugly on the cornea is a size 9.0 selected.

In the case of Acuvue Oasys, fit always starts at size 8.4 no matter what base curvature your previous lenses have. Evaluate the fit of the 8.4 lens on the cornea and only in the case of a snug fit of the 8.4 Oasys is the 8.8 size or a different lens design (i.e. different brand) selected.

Daria 11/23/17

Hello! I used to take 1-Day Acuvue Trueye -3.75 lenses with 8.5 curvature. Now, to save money, I want to switch to 2-week lenses and have chosen Acuvue Oasys. But there the curvature is only 8.4 and 8.7. Which ones to choose?

Natalia Gusakova 30.08.17

Vitaly, hello! The comfort in lenses depends on many factors including. Evaluating proper lens fit is an important consideration in choosing lens size, without evaluating fit it is not possible to tell which base curvature size and lens diameter is optimal for you. At the same time, lenses made of different materials having the same dimensions will sit on the cornea in completely different ways. Unpleasant sensations in the lenses can be not only due to improper fit, but also due to an inappropriate solution, with conjunctivitis, meibomyitis, with.

Vitaly 08/28/17

Hello, I'm getting contact lenses, I wear them for 6 days. The left eye is almost accustomed, and the right one seems to be blowing in the eye. Lens parameters: radius of curvature 8.6, diameter 14.00 mm. I tried contact lenses with the same radius, but with a diameter of 14.1 mm, there were other unpleasant sensations in the eyes, constant sensations of obstructions in the eye. Please tell me if a diameter of 13.8 mm is suitable for my right eye? Or what do you recommend? Best regards, Vitaly