The prescription for glasses and what is written in it. What does a cylinder mean in a glasses prescription? What is c 1.5 1 in glasses

Understanding what your doctor wrote in your glasses prescription is as easy as shelling pears! After reading the article, in a few minutes you will know what “sphere”, “addition”, “cylinder”, “axis” and “prism” are and what OD, OS, OU, DP, SPH, ADD, CYL, AXIS and P.D. You will easily understand any prescription and figure out what is wrong with your eyes and what optics modern medicine can help you with.

We receive approximately 90% of information about the world around us through vision. Such active use of the eyes very often leads to the fact that sooner or later problems arise with them, for which we are forced to consult a doctor. After the examination get a prescription for glasses and, naturally, there is a desire to read and understand it. It seems very challenging task. But in fact, it’s quite simple to figure it out if you know for what vision problems glasses are prescribed and what the letters and numbers in the prescription mean.

What are the types of vision problems and what types of glasses are there?

Points are usually issued in the following cases:.

Depending on the disease and visual defect, they can be used the following types of glasses:

for myopia, farsightedness and presbyopia, spherical (stigmatic) glasses are prescribed;
for astigmatism - cylindrical (astigmatic);
with strabismus - prismatic.

There are also multifocal glasses(bifocal and progressive) and combined (bifocal astigmatic and prismatic astigmatic). Bifocals have two optical areas: the upper one is used for distance vision, and the lower one is used for near vision, for example, when reading. If there is no obvious boundary between the focal areas, and the transition is smooth, then such glasses are progressive. Prismatic glasses are used for stabismus (squint).

Basic concepts and notations: OD, OS, OU, and DP

In medicine Latin terminology adopted. A prescription from an ophthalmologist or ophthalmologist is no exception.

Optical power: SPH, CYL and PD

Optical power is indicated in diopters(in recipes denoted D, D or diopter) and characterizes the refractive power of the lens, the degree of deflection of rays passing through it. The optical power of spherical lenses is indicated by SPH, cylindrical - CYL, prismatic - PD or, if the form is filled out by hand, by a triangle icon.

The “+” sign and the Latin word “convex” (convex lens) mean farsightedness, the “-” sign and the word “concave” (concave lens) mean myopia.

CYL and AXIS: correction of astigmatism

For vision correction in case of impaired correct form cornea or lens (astigmatism), glasses with cylindrical lenses are used. The recipe contains:

The optical power of a cylindrical lens (CYL) and the farsightedness sign “+” for hyperopic astigmatism or the myopia sign “-” for myopic astigmatism.
AXIS or AX - cylinder axis angle in the range from 0 to 180°.

PD and Prism Base Direction: Strabismus Correction

To correct stabilism, they are used glasses with prismatic lenses, for which the following parameters are specified:

Prismatic lens power (PD or triangle icon).
Orientation of the base of the prism: outward (toward the temple) or inward (toward the nose), up or down.

Bifocals and progressive glasses: addition (ADD)

This section is devoted to more complex, from an optical point of view, glasses with several focuses (multifocal) and their main characteristic - addition. As already mentioned, multifocal glasses include glasses with two focuses, for near and distance, (bifocals) and progressive glasses with a gradient (smooth) change in focal length.

Addition (ADD) or, as professionals say, “near gain” is the difference in optical power between near vision and distance vision. For example, if glass should be used to correct the clarity of perception of objects at long distances optical power+1.0D, and for close distances +1.5D, then the addition will be +0.5D.

It should be kept in mind that the addition value cannot exceed +3.0D.

Examples

Now we have everything necessary information to decipher any glasses prescription. We know how eyes are designated and the distance between them; what is SPH, CYL and cylinder axis angle; PD and direction of the base of the pyramid. We've covered addition and multi-trick points. Now we can correctly understand what diagnosis has been made and what optics are recommended.

Example 1

Addition (ADD) is indicated, so lenses must be bifocal or progressive. Farsightedness of both eyes (OU) is the same and its value is +1.5D (SPH) for long distances and +2.5D for close distances (SPH+ADD).
Distance between pupils (DP) - 61 mm.

If this is your first time receiving a prescription for glasses, then most likely you will not understand what all the symbols indicated in it mean. Even experienced glasses users do not always clearly understand what is written in it. Read this note and you will have a clear idea of what all these letters and numbers mean.

There is a certain order in which all prescriptions for spectacle correction. They may differ in design, the order in which the symbols are used, but if you understand the general scheme, then it will not be difficult to understand any recipe.

What designations are presented in a standard prescription for corrective glasses?

Traditionally, all prescriptions for glasses, as well as contact lenses start with icons OD andOS are abbreviations of the Latin terms “oculus dexter” (right eye) and “oculus sinister” (left eye). If the same correction is prescribed for the right and left eyes, the designation may be indicated OU is an abbreviation of the Latin term "oculus uterque" (both eyes). Instead of OD, some recipes have the designation R or Right for the right eye, and L or Left for the left eye.

If the icon for a particular eye is followed by Plano, 0.00, it means that you do not need optical correction for that eye.
Also in the recipe, when quantitatively describing the selected correction, the following symbols will be present: SPH,C.Y.L.AXISADDITION (ADD).
SPH- denotes optical power lenses in diopters necessary to correct myopia or farsightedness. The “-” icon means that you need negative power lenses to correct myopia, “+” - you need positive power lenses to correct farsightedness.
CYL (CYLINDER) - the numbers given after this designation show the correction you need in diopters in the presence of astigmatism. Clarity of vision with astigmatism is achieved by using cylindrical lenses. If there is astigmatism and it is necessary to correct myopia or farsightedness, negative or positive spectacle lenses with a cylindrical component are used. Often such lenses are simply called astigmatic. The cylinder value can be minus - to correct myopic (nearsighted) astigmatism, or positive - to correct hypermetropic (farsighted) astigmatism.
AX (AXIS) - the numbers after this designation indicate the position of the cylinder axis in degrees from 0 to 180. This designation should be present in the prescription only if astigmatism correction is necessary.
ADDITION (ADD)- addition or correction for near - the amount of optical power of the lens in diopters added to your prescription for distance if you need glasses for clear vision when reading or working on close range. As a rule, Add- shows the difference in diopters between the optical power in the zones for distance vision and for work at close range in the manufacture of bifocals and progressive glasses for the correction of presbyopia. Add always has a (+) sign and in the vast majority of cases does not exceed 3 diopters. If you need lenses of -2.0 diopters for distance vision and -0.5 diopters for near vision, then the addition will be +1.5 diopters.
In some cases, the amount of addition may not be indicated in the prescription for progressive lenses, but then it will have two values of the selected correction - for distance and for near. For example, for distance - OD: SPH -4.50 D, OS: SPH -3.00 D, and for near (for reading) OD: SPH -2.50 D OS: SPH -1.00 D. The amount of addition in this case will be equal to +2.00 diopters. The addition value for the right and left eyes should generally be the same.
is the power of a prismatic lens, which is indicated in prismatic diopters designated Pdptr or p.d. or a triangle icon if the eye doctor or optometrist is filling out the prescription by hand. Typically, prismatic lenses are used to correct strabismus. When assigning them, it is necessary to indicate in which direction the base of the prism is facing (Base) - base up (base up), down (base down), towards the nose (base in), towards the temple base out).
In the prescription, the optical power of the lenses is indicated in gradations of 0.25 diopters - for example, 3.75 diopters, 0.25 diopters, etc. Prismatic diopters are rounded to half values -0.5 p.d.
P.D.(pupil distance) or Dp(distancia pupilorum) or RC- the distance between the centers of the pupils in millimeters, for example 64 mm, 72 mm. When ordering individual, progressive and complex lenses P.D. should be indicated monocularly for each eye, for example OD - 31 mm, OS - 33 mm. In some cases, the PD values for distance and near are indicated separately, and the PD for distance is greater than for near. The correct PD value is very important for installing complex lenses into frames, so its exact value should be determined by a specialist, and not written into the prescription from your words.
Let's look at examples of descriptions of corrections in a glasses prescription:
1. OD sph-3.5 cyl -1.5 ax 80 (sph-1.5 - 1.0 x 90)
OS sph -4,.0
This means that the right eye has a spherical myopia correction with a -3.5 D lens, but there is also astigmatism, which is corrected with a negative cylindrical lens of 1.0 D, and the cylinder axis is located at an angle of 80 degrees. For the left eye, a spherical correction with a negative lens was selected - 4.0 diopters.
2. OU: sph +1.5 add +2.0 - in this recipe, an optical power for distance of +1.05 diopters and an addition of +2.0 diopters are assigned for each eye.
Some prescriptions indicate data on additional measurements that are carried out when selecting individual single-vision or progressive lenses - the height of the center of the pupil for each eye, the vertex distance (the distance from the cornea to the lens), the pantoscopic angle of the frame, the bend angle of the frame, and others. To optimize the thickness of the lenses, the shape of the light field of the selected frame can be drawn directly in the prescription, as well as the designations used for the selected optical coating - hardening, brightening, multifunctional - and also the color you want for the spectacle lenses.

Please note that a printout obtained from measurements on an autorefractometer cannot be used as a prescription for making glasses. Based on the data obtained with this device, it is possible to determine the objective refraction and estimate the direction of the cylinder axis in case of astigmatism. The final “subjective” correction is selected by a specialist - an ophthalmologist or optometrist based on various diagnostic tests.

25-05-2014, 17:44

Description

FINAL INVESTIGATION IN NATURAL CONDITIONS

This stage is the main one and cannot be skipped: it is here that the decision on assigning points is made.

Repeated examination in natural conditions includes monocular and then binocular selection of lenses for distance and selection of additional lenses for near.

Monocular selection for distance. The exact lenses that were determined as a result of all clarifying tests for cycloplegia are placed in the sockets of the trial frame. The visual acuity of each eye is examined in turn. If visual acuity is not lower than that determined by wide pupil, move on to binocular selection. More often, however, due to the usual tone of accommodation, it is reduced.

In this case, you should first of all try to change the spherical component of the correction: weaken the positive or strengthen the negative lens. The strength of the additional negative lens restoring maximum visual acuity will indicate the magnitude of the usual accommodation tone.

In hypermetropia, it plays a corrective role, and in myopia, on the contrary, it enhances ametropia. Therefore, the attitude towards it is different: with hypermetropia it should be taken into account when prescribing a correction, with myopia - strive for its complete relaxation. However, even with hypermetropia, a high habitual accommodation tone (above 2,5 diopter) is undesirable, since it is unstable and does not provide high vision in unfavorable conditions.

With myopia, the accommodation tone is up to 0,75 DPT is conventionally considered normal. To remove it, it is enough to carry out “fogging” according to Sheard, sometimes it disappears at once with two open eyes. Only in rare cases does the usual accommodation tone exceed critical values. In this case, one has to resort to long-term atropinization and wear glasses at the height of cycloplegia.

Usually, after several days of wearing glasses, the excess accommodation tone disappears and visual acuity reaches maximum. Long-term treatment of pseudomyopia with the use of medicines and exercises.

So, as a result of studying the accommodation tone, the same spherical correction or a slightly weaker one (in the case of hypermetropia) is left.

If none of the spherical lenses restore the initially achieved visual acuity, then the cylinder must be checked. In this case, an improvement in visual acuity can be achieved by weakening or increasing its strength. In the first case, the strength of the Cylinder in the frame is reduced to the optimal value (giving the highest visual acuity), in the second case it is left the same, since the uneven accommodation tone, which increases astigmatism, is undesirable and must be eliminated.

Finally, it may turn out that in order to restore the previous visual acuity it is necessary to rotate the axis of the correcting cylinder: an axial test is carried out with a crossed cylinder and the new optimal position of the axis is determined. A significant difference from its original position is most often due to prolonged wearing of glasses with an erroneously installed cylinder, i.e., the axis of which does not correspond to the main section of the astigmatic eye.

In these cases, it is advisable to prescribe correction according to the new axis position established for cycloplegia. If the patient has not previously worn astigmatic glasses, then the discrepancy may be explained by uneven accommodation. In these cases, it is recommended to choose for the cylinder axis the average direction between its positions with a narrow and wide pupil.

Thus, examination under conditions of cycloplegia is necessary mainly for accurate diagnosis of the main sections of astigmatism and for determining the boundary values of the sphere and cylinder. Under natural conditions, it is determined how much these values can be reduced, while it is undesirable to correct the axis of a cylindrical lens.

Bipocular selection for distance. In order to make sure that the patient will tolerate glasses well, the participation of both eyes in the act of vision should be checked.

Such balance must mean that three conditions are met:

equal tension of accommodation of both eyes and focusing them on the object in question (accommodative-refractive equilibrium);
the direction of the visual lines of both eyes towards the object in question (muscular balance, or orthophoria);
the same size of images of this object on the retinas of both eyes (equilibrium in image size, or iseikonia).

To evaluate them, there are special devices in which, using Polaroid glasses, rasters or other devices, images are shown separately for the right and left eyes, and the person being examined does not know which eye and what he sees. The device was produced in the former USSR RRD-1(raster separator for distance).

On its screen they show one of two figures - a cross consisting of four identical rectangular beams, or “brackets” - two equal rectangular letters WITH, directed with ends towards each other (Fig. 96). The same figures are available in foreign projectors or special devices with Polaroid field separation (for example, Haase's Polateste).

Examined from a distance 5 m sees the vertical beams of the cross with one eye, and the horizontal beams of the cross with the other; when showing “brackets”, he sees the right one with one eye, and the other - left side figures.

Accommodative-refractive balance is determined by the equal clarity of vision of all beams of the cross, muscular balance - by the symmetry of its image, and iseikonia - by the equality of the sizes of the “brackets”.

The first type of equilibrium is practically of greatest importance. Equal clarity of the beams of the cross is achieved by substituting spherical lenses ±0.25 diopter in front of the worse seeing eye. Muscle balance should be examined if the patient is dissatisfied with the selected glasses (i.e. 4 -th stage of the examination). The need to study iseikonia arises extremely rarely - only when correcting high-grade anisometropia.

In the absence of a device RRD-1 A sequential binocular test is recommended: the patient with selected lenses observes the smallest optotypes distinguishable by him; The person conducting the examination alternately covers the patient’s right and then the left eye with a shield. If the patient notices a difference in the clarity of the signs, the examiner adds +0,25 diopter or - 0,25 diopter in front of the worse seeing eye. This procedure is continued until the clarity of vision in both eyes is equal. The test is successful if the visual acuity of both eyes is equal (no amblyopia) and if the difference in their refraction is no more than 2,0 diopter

Before prescription of glasses, the patient is recommended to wear the selected lenses in a trial frame for 10-15 min. If the patient does not tolerate the correction well, then it is necessary first of all to reduce the difference in the power of the spheres of the two eyes by reducing the lens power by worst eye. If this does not help, then reduce the strength of the cylinders in both eyes, and if this is not enough, then reduce the strength of the spheres. At the same time, a feeling of comfort is achieved due to a slight decrease in visual acuity.

Selection of glasses or additional lenses for near vision. The selection of separate lenses for near may be necessary for presbyopia, as well as for insufficiency of accommodation at a young age. The latter especially often accompanies initial myopia in children and adolescents.

The selection is carried out with two eyes open. Lenses selected for distance are inserted into the sockets of the trial frame, and positive spherical lenses identical for both eyes are added. The patient reads text No. 4 of the table to determine near visual acuity, located at 33 see before his eyes. It is best to use a device for this POZB-1 or other near vision device.

Choose lenses with which reading text is most convenient. There is no such strictly substantiated methodology as for selecting lenses for distance, but for selecting glasses for near. There are several ways to select the optimal correction.

Duochrome test - select lenses that give equal clarity of characters on a red and green background (at a distance 33 cm).

Distance reserve test - determine those lenses with which reading can be done without difficulty from a distance 33 ± 7 see, and then 60 years - from a distance 33 ± 5 cm, the glasses set the eyes to the middle of the “comfort zone”.

Relative accommodation reserve test - determine the weakest positive lens with which it is possible to read the text, then add it to it + 1,5 diopters, and in older people 55 years - +1,0 diopter

In case of presbyopia, the age of the subject also serves as a “compass”. Approximately the power of additional lenses is equal to the patient’s age minus 30 , divided by 10 :

Where D- power of additional lenses, diopters;

A- patient’s age, years (if older 60 years A is taken for 60 .

When accommodation weakens due to age, the strength of additional lenses is determined by the degree of this weakening, i.e., the level of relative accommodation reserve. Usually it ranges from 1,5 before 3,0 diopter

It should be borne in mind that if absolute visual acuity is not reduced and reading is possible at a normal distance ( 33 cm), then the power of additional lenses should not exceed 3,0 diopter

After determining the strength of the lenses for distance, and if necessary, for near, the interpupillary distance is measured and glasses are prescribed.

We do not describe the fitting technology for multifocal glasses (i.e., progressive lenses) here. It requires special sets of these lenses and a device to measure convergence when changing the direction of gaze.

Rules for prescribing corrective glasses. The effectiveness of optical correction of visual impairment in ametropia largely depends not only on correct selection glasses, but also on the accuracy of their manufacture.

To avoid possible errors when writing prescriptions and making glasses, doctors and opticians must adhere to a unified designation system for optical correction devices.

Here are the basic rules for drawing up prescriptions for different types of corrective glasses.

General rules. Your glasses prescription contains the following required information:

date of discharge;
patient's last name (if he is younger than 14 years, then age is indicated);
doctor's name;
parameters of spectacle lenses, first for the right, then for the left eye;
the distance between the optical centers of spectacle lenses;
purpose of glasses (for distance, for constant wearing, for working at close range).

In addition, a prescription for glasses may contain the following information: basic parameters of the patient’s face necessary for choosing frames; the need for decentration of spectacle lenses; other features related to the lenses or frame.

There are special instruments to measure the distance between the centers of the pupils. In Fig. 97 shows a distance meter between the centers of the pupils ( IRG-65). The procedure for working with it is as follows. The device is positioned so that the index movement handles face down.

Apply the device with the nose pad to the bridge of the patient’s nose and ask him to look at the fixation mark. In this case, the examiner sees both eyes of the patient and the scales and indices in front of him. Using handles located on the underside of the body, the examiner alternately sets the indices so that they divide the pupils of the eyes in half, and determines the interpupillary distance using a scale.

In the absence of a device IRG-65 the distance between the centers of the pupils can be determined using a measuring ruler for selection spectacle frames or a regular ruler. The doctor is at a distance 30-35 cm from the face of a patient who is looking at some distant object over the doctor's head. Then the doctor places a ruler on the bridge of the patient’s nose and sights the position of the center of the pupil of his right eye with his left eye, and of the left eye with his right; using the ruler divisions, determines the interpupillary distance in distance glasses.

The interpupillary distance is measured in a similar way using glasses for near, but at the same time the patient looks at the bridge of the nose of the doctor, who sights both pupils with one eye.

Calculations show that with interpupillary distance 60 mm and distance from eyes to object 33 cm the distance between the centers of the lenses in glasses for near vision should be 5 mm less than with distance glasses. It is this difference that is taken into account in sintered bifocal lens blanks: the center of the lower segment of the lens for each eye is shifted by 2,5 mm towards the nose in relation to the center of the main lens.

Rules for prescribing spectacle lenses. Spectacle lenses can be single- or multifocal.

Each of these types of lenses may include the following optical elements: spherical, astigmatic, prismatic, eikonic. In addition, spectacle lenses can be light-protective with different transmittance coefficients.

The following are the rules for prescribing single vision lenses. Spherical (stigmatic) lenses are prescribed as follows: after the designation sph(or in Russian - “sphere”) indicate the “+” sign for converging lenses and the “-” sign for diverging lenses and then the lens power in diopters ( D). Lens power is expressed as decimal, with a whole number of diopters after the decimal point put 0 . For example:

When prescribing astigmatic lenses, after the number indicating the power of the spherical element, put a comma, then the symbol cyl(or in Russian - “cylinder”) and indicate the sign and power of the cylindrical element in diopters, as well as the position of its axis (non-active section) on the international scale TABO. For example:

As already mentioned, the eikonic element is practically not used for the correction of aniseikonia; The eikonic effect is used only for the correction of low vision.

Instead of a comma, sometimes a combination sign (=) is used, which resembles an equals sign, but with convex stripes. For example:

Lately the symbol D often omitted. For example:

Abroad, the designation of spherocylindrical combinations is usually simplified: the sign and strength are put first spherical lens with two digits after the decimal point, then the sign and power of the cylindrical lens, instead of the word axis ( Oh) - multiplication sign - X.

The above script looks like this:

In the absence of a cylindrical lens, only the first number is given; in the absence of a spherical lens, instead of the first number, put 0,00 .

In our recipes, if there is no spherical element, its designation can be omitted. For example, instead of sph0.0 su1 +1.0Dah 10° allowed to write sy1 +1.0Dah 10°.

The position of the axis of the corrective cylindrical lens should be indicated on the diagram TABO arrow.

For complex astigmatism, a sphere and a cylinder of the same sign should be drawn, and for mixed astigmatism, the opposite sign should be drawn. It is not allowed to write a combination of two cylindrical elements in one lens.

If the selection of glasses was carried out with a cylinder of one sign, and you need to write out a cylinder of a different sign (for example, if for complex hypermetropic astigmatism, a trial selection is carried out with negative cylinders), then a transposition should be performed. In this case, a cylinder of one sign is replaced by a combination of a sphere of the same sign with a cylinder of the opposite sign with an axis located at an angle 90° relative to the original axis of the cylinder.

The rules of transposition are as follows: the sign of the cylinder is changed to the opposite, the direction of the axis is changed to perpendicular (i.e., it should be subtracted or added 90°), the sign of the sphere is changed to the opposite, and its strength is equal to algebraic sum sphere and cylinder in the original recording.

GOST 23265-78“Eyeglass lenses” for optical production and medical supply services provides a different system for designating the refraction of astigmatic lenses. It is not recommended for eyeglass prescriptions, but eye doctors and optometrists should know it to ensure that glasses are made correctly.

According to this system, to characterize an astigmatic lens, its three parameters are indicated in the following order:

the posterior apical refraction is less than the refractive cross section (for positive lenses it is smaller in absolute value, for negative lenses it is correspondingly larger);
posterior apical refraction is greater than the refractive section;
direction of the main section with the lowest refraction on the scale TABO in degrees.

Examples of converting the sphere - cylinder system into the system GOST 23265-78 are given in table. 9.

In Russia, lenses with an astigmatic difference of up to 4,0 diopter and posterior apical refraction from- 30 before +20 diopter With an astigmatic difference up to 2,0 diopter intervals between the values of a cylindrical element are 0,25 diopter, over 2,0 diopter - 0,5 diopter

When prescribing glasses with prismatic action (after characterizing the spherical and cylindrical elements), the power of the prismatic element is indicated in prismatic diopters ( ? ) and the direction of the top-bottom line on the scale TABO. In this case the scale TABO continues until 360°.

Just like spherical and cylindrical lenses, prisms can be written in Latin and Russian transcription: prism - Rr, base - bas. For example:

When the top-base line is in a horizontal position, it is allowed to indicate its direction with the words: “base to the nose” and “base to the temple” - “ bas nas " And " bas temp ».

In other positions of this line, its direction should be indicated on a circular scale TABO with obligatory designation by an arrow according to the diagram.

When prescribing glasses with a prismatic effect, the force of the corrective prism should be “distributed” approximately equally between the two eyes, that is, the prismatic element should be approximately the same in each eye, and the top-base line should have the opposite direction.

For example, if it is necessary to correct exophoria 6,0 Prisms should be prescribed:

When correcting combined heterophoria corrected with a prism 8,0 prdptr base 30° in front of the right eye, you should write:

According to existing standards, it is allowed to write prismatic elements with a force of 0,5 before 10 prdptr.

The following are rules for prescribing multifocal lenses. The most commonly used lenses are bifocal lenses. They are written out in the form of a fraction, the numerator of which indicates the characteristics of the elements of the upper part, and the denominator indicates the characteristics of the lower part of the lens according to the rules given above.

For example:

Since the segment of the lens used for working at near distances differs from the main part of the lens only by the addition of a spherical component (usually the same in both eyes), a second method of prescribing bifocals is often used: after indicating all the components of the lenses for distance, the refractive power of the additional spherical lens for distance is indicated. close.

For example:

Recently, most often they do not write “bottom” and “top”, but after the designation of lenses intended for distance vision for both eyes, they indicate: the addition for near is so many diopters. For example:

In English-speaking countries they write “n.a.” ( near addition).

Please note that only spherical bifocal lenses are commercially available ( GOST 23265-78).

Trifocal lenses are written in three rows separated by lines. For example:

Bifocal spheroprismatic glasses, prescribed to relieve accommodation and convergence, are prescribed as follows: after distance lenses (they must be non-astigmatic and the difference between the two lenses should not exceed 2,5 diopters) write " BSPO" For example:

After characterizing the refractive properties of spectacle lenses, their light transmission properties can be indicated. In this case, the light transmittance coefficient is indicated ( 25, 50 or 75% ). It is also possible to designate the color of the lens. For example:

Green filters 25%.

Smoke filters (neutral) 50%.

When prescribing glasses containing lenses of non-serial manufacture (including non-astigmatic and astigmatic elements exceeding the values provided by the standards; including prismatic elements; astigmatic lenses with light-protective properties; trifocal lenses), the patient should indicate the point where these glasses can be manufactured.

Rules for prescribing spectacle frames. In a typical prescription, one parameter related to the spectacle frame is indicated - the distance between the centers of the spectacle lenses, which corresponds to the distance between the centers of the patient's pupils. All other parameters of the frame are determined by trial fitting it to the patient’s face directly when placing an order for glasses in an optical store.

If there is a discrepancy between the size of the face and the distance between the pupils of the patient, or if the patient wishes to choose a wide modern frame, the distance between the centers of the openings is much greater than its interpupillary distance, it becomes necessary to shift the centers of the lenses towards the nose.

The minimum diameter of an unfaceted lens required to obtain such decentration can be determined by the formula:

Where L- diameter of the unfaceted lens;

A- width of the spectacle frame opening;

b- width of the nose of the spectacle frame;

Dp- the distance between the centers of the lenses that should be of this patient wearing these glasses.

We remind you that the values " A" And " b» marked on inside one of the temples of the frame in the form of a shot A/b. Decentration of lenses towards the temple is much less common. In this case, the minimum diameter of an unfaceted lens is determined by the formula:

If it is impossible to order in person, the glasses prescription should indicate the basic facial parameters necessary for selecting frames, namely:

A p And A l- distance from the center of the bridge of the nose to the centers of the pupils of the right and left eyes, mm;

B- nose bridge width, mm;

IN- distance between the bases of the ears, mm;

G- distance between temples, mm;

D- nose bridge height, mm;

E- temple length, mm.

These parameters can be determined using the spectacle frame fitting ruler included in the spectacle lens trial kits.

Distance A p And A l determined by grid scale 5 , while the zero point of the base recess 1 placed on the center of the bridge of the nose. Using the scale on this recess, the width of the nose bridge is determined. B. Distances IN And G measured using a scale 2 , while the doctor uses his left eye to visualize the position of the right auricle and right temple, and with the right eye - the position of the left auricle and left temple of the subject. Determining nose bridge height D and temple length E clear from the picture. However, it is still preferable to select frames in person.

Prescription form for glasses. To unify the prescription of glasses and more fully reflect all the characteristics of lenses and frames, two versions of the prescription form for glasses have been developed.

The first option is intended for prescribing the most popular single-vision spherical and astigmatic glasses (Fig. 98). The “Note” column may contain additional information regarding spectacle lenses and frames. This form is intended for in-person ordering, i.e. in this case, the patient must select the frame himself with the help of a qualified optician.

The second option - full (Fig. 99) - is intended for prescribing single-vision and bifocal glasses, containing, along with spherical and astigmatic, also prismatic elements. The front side is filled in in all cases: all information about spectacle lenses. The position of the axes of the astigmatic element is indicated in the diagram by a line. The direction of the line top - base of the prismatic element is indicated in the same diagram by an arrow.

The reverse side of the form is filled out only when ordering glasses in absentia, when it is not possible to directly select the frames to suit the patient’s face. In this case, all the necessary dimensions of the face are indicated ( A p, A l, B, C, G, D, E), measured using a ruler or caliper, as well as the required distance from back surface lenses up to the eye ( AND).

EXAMINATION OF A PATIENT WITH READY GLASSES

The examination is carried out no earlier than after 2 weeks after the patient started using glasses. This period is enough to get used to the glasses or identify their shortcomings.

If the patient is not satisfied with the glasses, then it is necessary to identify the reason for this. First, compliance with their recipe is established. The power of lenses is checked using a diopter meter or using the neutralization method. Then the correct position of the glasses on the face is determined. The correspondence between the centers of the lenses and the centers of the pupils is checked using a centriscope.

You can also mark the position of the lens centers on the diopter meter.

The displacement of both lens centers by the same distance in the same direction (for example, up or down) is not a defect.

Shifting centers in opposite directions horizontally (i.e. increasing or decreasing the distance between the centers of lenses compared to the interpupillary distance) is permissible within the following limits: for lenses with a power of up to 0,5 diopter ±6 mm, for lenses 0,75...1,0 diopter ±4 mm, for lenses above 1,0 diopter ±2 mm.

With large deviations, a prismatic effect occurs and glasses-induced heterophoria occurs. And since exophoria causes less discomfort than esophoria, in glasses with negative lenses the patient can more easily tolerate a shift of centers outward, and with positive lenses, inward.

The patient tolerates the relative vertical displacement of the lens centers especially poorly. For lenses up to 2,0 diopter it should not exceed 2 mm, for lenses above 2,0 diopter - 1 mm.

For lenses of high refraction, for example when correcting aphakia, even these tolerances established by GOST may turn out to be too high. When patients complain of diplopia and it is eliminated with the help of prisms, the glasses have to be remade.

Next, check the distance of the lenses from the top of the cornea using a keratometer or a regular ruler. The accuracy of this measurement is not very high, since it is impossible to see the rear pole of the lens from the side. Measure the distance from the top of the cornea to the edge of the frame and add 1 mm. The normal distance of the lens from the eye is 12 mm. Its increase enhances the effect of positive and weakens the effect of negative lenses. The permissible deviations in the distance of lenses from the cornea are as follows: for lenses up to ±0.75 diopter ±10 mm, 1,0...3,75 diopter ±5 mm, 4...6,5 diopter ±3 mm, 7..8,5 diopter ±2 mm, 9...12,5 diopter ±1.5 mm, 13...20 diopter ±1 mm.

If the glasses fully comply with the prescription and their position on the face is also correct, then intolerance may be due to physiological reasons.

The most common of them is heterophoria. Heterophoria in glasses is studied with a point light source and a Maddox cylinder. Prisms that correct heterophoria are selected and glasses with prismatic elements are prescribed.

The main symptom of incorrect distance of glasses from the eye is deterioration in visual acuity in ready-made glasses, compared to what was achieved during the trial selection. In these cases, you should try attaching an additional lens from ±0.25 before ±1.0 diopter The lens with which the highest visual acuity is restored will indicate the magnitude of the error. In this case, you should weigh how best to eliminate it: choose a new frame or insert new lenses into the frame chosen by the patient.

In this regard, it should be noted that when prescribing glasses with strong lenses (with a spherical lens above ±8.0 diopters) it is recommended to examine the patient with the selected frame. The approximate tolerance of future glasses can be assessed by attaching selected lenses to it using the so-called Halberg clip.

Another reason for intolerance is the distortion of the perception of spatial relationships introduced by glasses. Positive lenses give an apparent magnification of objects, negative lenses make them appear smaller. Astigmatic lenses have the property of distortion, as a result of which the shape of objects changes - they stretch horizontally or vertically, some objects move away, others come closer.

This can, for example, make it difficult to walk up stairs: the steps seem too close or too far away. The difference in the power of the lenses of the two eyes can cause symptoms characteristic of aniseikonia: with a difference in the power of spherical lenses - a feeling of interference with vision, sometimes double vision of objects (general aniseikonia), with a difference in the power of cylindrical lenses, an increase and approach to the observer of one side of objects, the right or left (meridional aniseikonia).

In case of such complaints, the power of the corrective lenses should be slightly weakened: in case of isometropia - on both eyes, and in case of anisometropia - in the worse eye. At the same time, they make a compromise: at the expense of some deterioration in visual acuity, they achieve a feeling of comfort.

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OD, OS and other abbreviations

The abbreviations OD and OS are short terms for the Latin terminology “oculus dexter”, “oculus sinister”, which means “right eye” and “left eye”. The abbreviation OU is also often found, from the abbreviation “oculus uterque”, which means “both eyes”.

This is the professional terminology of ophthalmologists and optometrists, used when filling out a prescription for any type of glasses or eye drops.

Please note that in ophthalmology, all information about the right eye is always indicated first, and then about the left eye. This is how doctors insure themselves against confusion and mistakes. Therefore, your recipe will say exactly that. In addition, it will also contain other abbreviations. Eg:

Sph (sphere), which translates as “sphere” and indicates the optical power of the lens, which is expressed in diopters. It is the power of the lens that plays the main role in correction, either. Moreover, when a “-” sign is indicated in front of the numerical value, this means that you are myopic. Myopia, or scientifically, is corrected by diverging minus lenses. Sometimes you can see the Latin “concave” above the minus sign.

If there is a “+” in front of the numerical value, then you are farsighted, and your glasses are for distance. Farsightedness, or farsightedness, is corrected with plus converging lenses, otherwise designated “convex”.

The concept of Cyl (Cylinder) - “cylinder” will indicate the optical power of the lenses that are used for correction. Astigmatism is an uneven, non-spherical surface in which refraction in one of its meridians occurs somewhat stronger than in the others. This anomaly can be corrected with cylindrical lenses. In this case, the recipe must indicate the position of the cylinder axis (from the Latin Axis or Ax), which is expressed in the degree range 0 - 180. This is due to the peculiarity of the refraction of light passing through a cylindrical lens. Moreover, only rays traveling strictly perpendicular to the cylinder axis are refracted. Rays running parallel to it do not change their direction. These properties make it possible to “correct” the refraction of light in a specific “offending” meridian.

Cylinder values can be either: or negative, i.e. designed to correct myopic astigmatism (for myopia), or plus - corrective hypermetropic astigmatism(for farsightedness).

The meridians are determined by applying a special scale to the front surface of one of the eyes. As a rule, such a scale is built into the frame sample, which is used for measuring and further selecting glasses. This scale, like the entire system, is called TABO.

Addition - Add - “addition for near”, a term denoting the difference in diopters that exists between the zones of distance vision and near vision, which is necessary in the manufacture of bifocal or progressive glasses intended for correction. That is, when you need +1.0D lenses to improve distance visual acuity, and +2.5D for near vision, the addition will be +1.5 D. In this case, the maximum addition value cannot exceed +3.0D.

Prism or prismatic lens power. This value is measured in prismatic diopters (that is, p.d. or triangle symbol when the recipe is written by hand). These lenses are used for correction, and when prescribed, depending on its type, they indicate which direction the base of the prism is facing: up, down, outwards (towards the temple), inwards (towards the nose).

The optical power of spherical or cylindrical lenses, as well as the addition value, is indicated in diopters, using a maximum refinement of up to 0.25D. Prismatic diopters may be rounded to their half values (e.g. -0.5p.d.)

The distance between the centers of the pupils (RC) - Dp (distancia pupilorum) - value measured in millimeters. It is noteworthy that for near it is 2 mm less than for distance. In recipes it can also be referred to as Dpp.

Prescription for glasses

OD sph-2.5 cyl -0.5 ax 90 (sph-2.5 - 0.5 x 45)

This recipe can be deciphered as follows:

For the right eye, spherical correction of myopia is indicated, using a -2.5D lens,

There is astigmatism, corrected by a minus cylindrical lens - 0.5D,

The cylinder axis is an inactive meridian, located along the 45o axis,

For the left eye, spherical correction is indicated using a 3.0D minus lens.

DP – interpupillary distance 64 mm.

OU sph +2.0 +0.5 add

Prescription for glasses and contact lenses

Sometimes people ask, can a glasses prescription be used to make contact lenses? The answer is clear - it’s impossible.

Prescriptions for both glasses and contact lenses have their own characteristics. The contact lens prescription must specify the base curvature as well as the diameter of the lenses. The contact lens is placed directly on the cornea and forms almost a single unit with the eye. optical system, glasses lenses, on the contrary, are located at some distance from the cornea (up to 12 mm). Therefore, in case of myopia, the power of contact lenses is slightly reduced, and in case of farsightedness, it is increased.

When choosing glasses or contact lenses, a prescription must be given to you. Be sure to save it and the next time you have your eyes checked, you can compare the results. In addition, if you have a prescription, you can order contact lenses or glasses at any optical shop you like, regardless of the location of the examination.

Visual impairment is already stressful in itself. And the prescription for glasses written out after visiting an ophthalmologist does not help in any way to calm you down. Understanding what is written on the form is quite capable of making our state of mind more calm.

In addition, it usually significantly increases confidence in the doctor who prescribed it.

Most often, a prescription is written on the form shown below.
As you can see, the parameters of the right eye come first, and then the left. This is a prerequisite for all ophthalmic prescriptions.
Here we will look at all the possible parameters that are entered in the form. But each specific recipe contains only a part of them. Those that concern this patient.

Thus, when prescribing glasses to correct strabismus, most likely there will be no addition correction (near correction). Correction of astigmatism is not always necessary, and, therefore, it will not be indicated.

Designations on the form for glasses of the right and left eyes

In our sample it is written “Right Eye” and “Left Eye”, but often doctors write OD for the right eye and OS for the left eye. Sometimes they write OU - this means both eyes. As already noted, be sure to start with the right eye first, and then the left.

Glasses help you see better using a lens system built into them. In fact, there may be three or even four (with bifocals). But most often only a combination of the two occurs.

Designations on the form for sphere glasses

This is the designation for the optical power of a spherical lens. It is marked “Sph” when writing a recipe by hand. Calculate the lens power in diopters (D or D) with a minimum step of 0.25 D. Here, there may also be two types of lenses:

scattering - they are marked with a “-” sign before the number, for example -1.75, and are prescribed in the presence of myopia (myopia). If you are prescribed glasses with a “-” symbol, this means that such a person has poor distance vision;
collecting ones, which are marked with a “+” sign in front of the number, for example + 2, 5, and are prescribed, accordingly, for farsightedness (hyperopia). When writing a prescription with a plus value of lenses, you need to think that the person has difficulties with reading and other similar actions at close range.

If bifocals or progressive glasses are prescribed for presbyopia, then two indicators “top” and “bottom” will be indicated here. But the difference between them should not exceed 3 D.

Symbols on the cylinder glasses form

These are cylindrical lenses designed to help the eye create a single focal system for astigmatism. They are designated “Cyl” when writing a recipe by hand. Here the position of the cylinder axis must be indicated in degrees from 0 to 180. This is due to the fact that light rays passing through the cylinder axis, depending on the degree of refraction, act differently:

if the ray is perpendicular to the axis, it is refracted;
if the ray travels parallel, it does not change its direction.

This property of a cylindrical lens allows you to correct astigmatism in the desired meridian and create a single focal system of the eye, which allows you to see objects more clearly. This indicator is indicated on the scale located at the bottom of the table. The indicator is set separately for the right and left eyes.

To determine the value of a cylindrical lens, a special TABO scale is used, which is placed on the frame during a vision examination (it has special notches and looks the same as in the prescription).

Cylindrical lenses for astigmatism correction can be of two types:

with a minus sign when correcting myopic astigmatism;
with a plus sign to correct farsighted astigmatism.

Data on the value of cylindrical lenses are indicated in the table with the corresponding sign in diopters. With step values up to 0.25 D.

Symbols on the form for axis glasses

This is a number that shows in which direction the astigmatism is developed; it will be expressed in degrees. Designated as "AH"
If there is no astigmatism, then this column of the form will be blank.
There is usually a gradation within 1, 5 or 10 degrees, but parts of a degree are never written.

Prism on glasses form

This type of lens is used to correct strabismus. This indicator “p.d.” or used to indicate the direction of squint. In this case, the base of the triangle indicates the direction of the prism, for example: towards the nose, outwards, etc. It is determined in diopters; the minimum step value must be at least 0.5 D.

It is present in prescriptions for glasses to correct strabismus. But it is not filled out in other forms.

Important! If your glasses prescription contains this icon, try ordering lenses and frames from your doctor. Try to have the fitting done by an ophthalmologist. Here, precise alignment of the pupil and lens is very important for treatment.

Reasons for receiving points

Additions are usually added here. Among them will be:
ADD – or reading supplement. Used with bifocal glasses.

Interpupillary distance

When selecting points, this indicator plays a very important role. important role. The correction lens must be located opposite the pupil. This is the only way the eye will get necessary correction, and not an additional load. An incorrectly placed lens will require additional eye strain, which can cause headaches, eye fatigue, and sometimes double vision.

The distance between the pupils is measured in millimeters. Can range from 40 to 70. Sometimes measured for each eye separately.

Important! Interpupillary distance (Dp) is not always indicated in the prescription. Therefore, he can be asked to indicate to order glasses that are more comfortable to use.

In our example form it is indicated below under the TAVO scale.

Assigning points on the form

The lowest part of the prescription will be the prescription of glasses. Usually the doctor explains exactly how to wear glasses. But the recipe also indicates this. So, the designations will indicate the following:

emphasized “For distance” (or Dist) - this type of glasses is worn all the time without taking it off. It is designed to correct myopia. Sometimes it is used for driving a car or watching TV;
“For work” (or Near) is highlighted – this type of glasses corrects presbyopia and will allow you to work at the computer, read, and sew without problems. They are used periodically and should not be worn all the time;
designated “For constant wear” (or Inter) – they are used to correct variable vision. As a rule, they use transition (bifocal) lenses.

How to read a recipe?

Now let's try to read the written prescription for glasses:

We see that the right eye has poor distance vision - 5.0 D, while there is astigmatism -0.5 D. with an axis degree of 50. The left eye also sees poorly, but astigmatism does not appear.

Glasses will need to be worn at all times. The distance between the pupils is 64 mm.

Prescription for contacts or glasses?

There is a difference between these two recipes. Since glasses are located at some distance from the eyes, lenses are also selected as vision correction. Lenses actually create a single optical system with the eye. Here the correction system will differ from glasses.

Therefore, different prescriptions are always written out for lenses and glasses with different data and on different forms. And you can't order glasses with a prescription for lenses. Exactly the same as vice versa - lenses with prescription glasses.