Daltonism in women

We are so used to seeing the world in all its diversity of colors that we can’t even imagine how it could be any other way. How can you see green foliage as brown or gray, or a ripe tomato as dark green or deep gray? It turns out you can. There is a small part of the planet’s population that sees the colors we are used to in a completely different way, sometimes without even suspecting it. Such people are called color blind, and they are mostly men. So is color blindness in women really just a myth, and the disease can actually be classified as a purely male pathology, like the infamous hemophilia?

Does color blindness occur in women?

No matter how much the weaker sex would like to consider themselves uninvolved in such a special type of visual impairment as color blindness, they are directly related to it. Moreover, this does not prevent them from suffering from color blindness actually 20 times less often than men.

Yes, statistics in this case are more cruel to the stronger sex. Although color blindness is considered a rare vision pathology, it is diagnosed, according to various data, in 2-8 representatives of the stronger sex out of 100. For women, this figure is much lower: only 4 representatives of the weaker sex out of 1000 see colors not as they really are.

But so far we have used only a generalized concept of pathology, which since 1794 has been called color blindness. And it all began with the fact that the English physicist John Dalton at the age of 26 accidentally learned about a certain feature of his vision. At one of the social parties, where John was invited as a guest, it turned out that he did not distinguish between the color red and its shades. He discovered the same feature in his brothers, which he later wrote about in his works.

It was only about the lack of perception of red and how the spectrum visible to a person is distorted. It was this syndrome that acquired the name "color blindness". It was later discovered that color perception disorder can have different shades: a person may not perceive a certain color, and depending on this, his picture of the world in a certain spectrum will not coincide with the generally accepted one, or see color in black and white tones. However, among the people, various color perception disorders are still commonly called color blindness.

In fact, the prevalence of various forms of color blindness differs among both men and women. Complete lack of color vision is extremely rare (1 person per million) and is almost never found in women. However, red-green vision impairment is typical for 5 women out of 1000 (for men, this figure is much higher: 8 people out of 100).

And yet, no matter how small the figure reflecting the incidence of color blindness in women, it indicates that color blindness is also characteristic of the weaker sex, but to a lesser extent than the stronger.

Causes color blindness in women

When we said that women have a direct connection with visual impairment, diagnosed mainly in men, we were not being disingenuous at all. And the issue here is not the peculiarities of male vision in the presence of women, and not violence against men by the weaker sex. The whole problem is in genetics. But let's not get ahead of ourselves, and try to figure out why the majority of people see the world in one color, and a relatively small group - in another.

Our eye, like many other organs of the human body, is far from a simple mechanism. It has a unique ability not only to distinguish objects, but also to see them in color. This ability is given to us by special nerve cells that can be found in the central part of the retina.

These unusual cells of the central nervous system are called color-sensitive receptors or cones. There should be 3 types of such receptors in the eye, and each of them is sensitive to a light wave of a certain frequency. Each type of cone contains a special pigment that is sensitive to a certain color: red, green or blue.

Perhaps the reader will have a legitimate question: what about the other colors that our eyes distinguish? Well, everything is extremely simple here, we see the other colors and shades as a result of mixing the 3 primary colors. For example, to see the bark of trees as it is, we only need to distinguish red and green colors, and to see an eggplant as purple, we need to distinguish blue and red shades. What can I say, in school, in drawing lessons, many experimented with watercolor paints, trying to get more and more new colors, so no one will have to discover America.

If we go deeper, we actually perceive waves of a certain length as color. We perceive a wave of up to 570 nanometers as red, a wave of no more than 443 nm as blue, and we attribute yellow to waves of up to 544 nm.

A person whose eyes perceive waves of different lengths sees colors as they are accepted to distinguish. Such people are usually called trichomata, which in translation from ancient Greek roughly means "three colors".

With color blindness, events can develop in 3 directions:

• absence of one of the pigments in the retina of the eye,
• decreased effectiveness of red, blue or yellow pigment,
• color blindness or lack of essential pigments.

In principle, one can speak of a disease in the literal sense of the word only in the latter case. And the absence or decrease in the effectiveness of the pigment is rather attributed to the peculiarities of vision, because a person still remains able to distinguish colors, even if not in the generally accepted sense. In addition, these people often distinguish more shades than those with normal vision. Here we are not talking about a disease, but about a deviation from the norm. What causes such deviations can be understood by examining the mechanism of pathology development.

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Pathogenesis

The pathogenesis of color blindness in women and men in most cases is based on an anomaly of the female chromosome, designated by the letter X. It is the X chromosome that is responsible for the carriage of a recessive trait, which, however, does not always manifest itself.

Let's remember from biology: the female sex chromosome set consists of 2 X chromosomes, and the male has one X and one Y chromosome. If a woman is a carrier of an abnormal X chromosome, she can pass on the recessive trait to her children. Boys and girls have equal chances to receive such a "gift" from their mother, but the probability of becoming colorblind is much lower for girls.

The explanation is simple. A girl receives an X chromosome from both her father and her mother. If the mother passes on the "wrong" chromosome to her daughter (she may have normal vision, being only a carrier of recessive information), a compensation mechanism is activated, that is, vision develops on the basis of the "correct" paternal X chromosome. But the girl, like her mother, becomes a carrier of the abnormal gene, which means she can pass it on to her children.

If a boy receives the "wrong" X chromosome, he has nothing to compensate for the recessive gene, because his genome contains only one such chromosome. This means that color blindness is more likely to be passed on to a son than to a daughter.

For a woman to be color blind, she must have received the recessive gene from both her mother and father. This is only possible if the father is color blind and the mother is at least a carrier of the abnormal chromosome. If only the father is affected and the mother is not prone to color blindness, their daughter is safe because the abnormal X chromosome from the father will not show up in the presence of the dominant healthy X chromosome from the mother.

Since color blindness is considered a recessive trait that rarely manifests itself in the presence of a dominant gene, the prevalence of the pathology remains small. The probability of a color blind man meeting a woman with an abnormal X chromosome is small, which means that the disease can only threaten daughters in exceptional cases.

But boys are unlucky in this regard. After all, they can inherit color blindness from their mother even if their father is healthy. The risk factors in this case are again the mother's carrier or illness, while the father's health does not affect the male offspring in any way, since they cannot inherit a recessive trait from a parent of the same sex.

So far we have been talking about congenital vision pathology. However, color blindness can also be acquired, in which case its symptoms do not always appear on a permanent basis.

The causes of acquired color blindness can be both physiological processes in the body and the use of certain medications (in the latter case, the symptoms can be both constant and transient). Physiological processes include aging of the body. Wear of the lens leads to its clouding (karatakte), which manifests itself not only in deterioration of visual acuity, but also in changes in color perception.

Another cause of color blindness in adults or children can be considered pathologies associated with eye trauma, if the retina or optic nerve were involved in the process.

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Symptoms color blindness in women

As we have already mentioned, color blindness can manifest itself in different ways. People with normal vision have certain patterns regarding colors and their meanings, so we all not only consider tree leaves to be green, but also see them that way.

Color blind people do not have such templates, because not all color blind people see the pictures of the surrounding world in the same way. The color range that a person with color perception disorder sees depends on which cones with which pigment are missing or less effective. In this regard, there are several types of color blindness, each of which has its own characteristic first signs and a certain range of colors and shades perceived by the eye.

Dichromacy is a vision disorder in which one of the primary colors is missing from the spectrum. Dichromats lack cones with one of the pigments in their retina: red, yellow, or blue. These people can also be divided into 3 subgroups:

• Protanopic dichromacy (protanopia) is the absence of red pigment,
• deuteranopic dichromacy (deuteranopia) is indicated by the absence of the pigment responsible for the perception of green color,
• In the absence of blue pigment, we speak of tritanopic dichromacy (tritanopia).

Conditions in which there is a weakening of any of the main pigments are called anomalous trichromacy. They can also be divided into subgroups:

• protanomaly - weakening of the activity of the red pigment,
• deuteranomaly - decreased efficiency of green pigment,
• tritanomaly - low efficiency of blue pigment.

The absence of all 3 pigments leads to the fact that a person sees the world in black and white tones, which in fact can be called different shades of gray. This pathology is called complete color blindness or achromatopsia.

One of the variants of achromatopsia can be considered monochromacy, when a person is able to distinguish only one color and its shades. In this case, there is no point in talking about color vision, because it is impossible to obtain other colors based on one color.

Achromatopsia and its variety monochromacy are extremely rare. The pathology affects mainly men. Most often, this pathology is accompanied by other symptoms: visual acuity impairment and nystagmus (involuntary pupillary movement).

In the case of absence or weakening of one of the pigments, we speak of partial color blindness, which is also typical for the female sex. Most often, there is a weakening of the red and green pigment (or both at once). Thus, 3-4 women out of 1000 suffer from deuteranomaly, and other disorders of the perception of the red-green spectrum are noted in only 0.1% of women. In the latter case, vision still remains colored, but color perception is even more distorted.

Blue color vision impairment is a rather rare type of vision pathology, which, by the way, has no gender preferences, since it is associated with gene distortions in chromosome 7. Both tritanopia and tritanomaly are found in 1 woman out of 100. The same statistics apply to men.

Acquired color blindness is characterized by problems with distinguishing yellow and blue colors. In this case, there is also no dependence on the patient's gender.

Complications and consequences

So, color blindness is nothing more than a violation of the perception of a certain part of the color spectrum, which leaves its mark on the colors in which a person sees the world around him. The most surprising thing is that color blind people most often do not suspect anything about their defect. From childhood, all children are taught to call colors by certain words: red, green, yellow, etc. Color blind children will, like everyone else, say that the leaves on the tree are green, even if in fact they see them in a different color, and this color will be considered green in the child's mind.

This feature of colorblind people often does not allow diagnosing the pathology at an early age. And only chance can make a person (or people close to him) think about how accurate his vision is in determining colors. Although, in principle, it is often not so important when the disease is detected, if it does not progress during life and has the same manifestations at any stage.

But on the other hand, color blindness can become an unexpected obstacle on the way to the goal, if a young man or woman has dreamed of becoming a pilot or a doctor since childhood. After all, if in childhood color blindness does not cause any inconvenience (after all, the child sees the world exactly like this from birth, and he has nothing to compare with), then in adulthood, when it comes to choosing a profession, the disease makes certain, not always pleasant adjustments.

Thus, color blind people are not suitable for professions where great importance is attached not only to visual acuity, but also to the correct perception of color. Drivers, pilots, doctors, machinists, sailors must have accurate vision, because the lives of other people often depend on how a person of such a profession navigates a situation. Color blindness can become an obstacle even to obtaining a driver's license, which gives the right to drive a personal car, not to mention public transport.

The most common types of color blindness are considered to be a distorted perception of red and green colors. However, it is these colors that are usually used as signal colors. It is the inability to adequately respond to signals that becomes an obstacle in professional activities and even in everyday life (for example, when crossing a road with a traffic light that has only 2 colors, color blind people can get lost).

Color blindness in women is unlikely to affect their happiness in marriage, but problems in professional activities and communication with other people can haunt them no less than men. Different color perception of people with normal vision and color blind people can lead to funny situations, as a result of which the latter can become a target for ridicule and pranks.

Some creative professions are also unavailable to colorblind women, such as painter, photographer (unless it is black and white photography), designer (it does not matter what you have to design: landscape, interior or clothing, color perception plays an important role in any case). Now many young women, along with men, go to serve in the police. Alas, such work is not suitable for colorblind people.

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Diagnostics color blindness in women

For an ophthalmologist, the gender of the patient who came to the appointment does not matter, therefore, the diagnosis of color blindness in women is the same as in men, using the same methods. People whose work requires perfect vision undergo color perception testing regularly as part of a professional examination by an ophthalmologist.

Color perception testing can be performed using three popular methods: spectral, electrophysiological, and pseudo-isochromatic tables (pigment).

The spectral method involves the use of special devices. Such devices include the Ebni device, the spectral anomaloscopes of Nagel and Rabkin, which were developed in different periods of the 20th century. The Rayleigh color equation is used in the operation of this equipment.

The pigment method is applied using polychromatic tables, which were developed at different times by many scientists (Stilling, Ishihara, Schaff, Fletcher together with Gamblin, Felhagen, Rabkin). Instead of tables, one can use the Edridge-Green lantern with light filters, the non-spectral anomaloscope of Demkina, the same device, improved by Rautian in 1950, and other similar instruments for studying color perception.

In our clinics, the most popular tables are those of the famous ophthalmologist Efim Borisovich Rabkin, the first edition of which was published in 1936, and the ninth in 1971. Rabkin developed his own method for the complete study of human color perception, which contains 27 main and auxiliary tables (control, for studying color vision in childhood, determining color thresholds, and the speed of color discrimination).

Each of the main or control tables consists of dots of different sizes and colors. With normal vision, a person can see certain numbers and geometric figures on these tables. People with impaired color perception either do not see the picture at all, or see the picture distorted, as a result of which they can name completely different numbers and figures, describe only individual parts of the dot pattern on the table.

Rabkin's tables are accompanied by a methodology for their use, written by the author of the tables and published in 1971. Depending on what exactly patients see on the tables, one can make an accurate conclusion about the type of color blindness.

The tables are shown to patients one by one, placed vertically at the patient's eye level. A series of tables are shown from a distance of half a meter to a meter for 5 to 10 minutes (only 5-7 seconds are allocated for studying each table; in the case of an uncertain answer, the display is repeated). The lighting should be within 400-500 lux (natural light or daylight lamps that do not distort the color spectrum).

The diagnostics are carried out for each eye separately. The doctor fills out a special card for each patient, where he makes notes for each table (plus, minus or question mark).

Using 27 basic Rabkin tables allows to determine the type and degree of color blindness with great accuracy, however, the cause of the pathology remains hidden from the doctor's eyes. Auxiliary tables help to clarify the nuances of human visual perception (for example, visual acuity, reaction speed, etc.).

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Differential diagnosis

Differential diagnostics is carried out between congenital pathology of color perception and a disorder caused by the use of a certain group of medications or eye diseases (cataract, glaucoma, eye injuries with damage to the optic nerve or retina). It also plays a major role in assessing professional suitability and the ability to serve in the military.

The electrophysiological method is used to study the features of color perception in various pathologies. Thus, chromatic perimetry is indicated if there are suspicions of pathologies of the optic nerve or central visual pathways, which are equally capable of causing color blindness in both men and women. Electroretinography is a method that allows determining color blindness by the functional state of the pigment cones in the eye structure.

Treatment color blindness in women

Since in most cases color blindness in women develops due to eye diseases, these diseases need to be treated first. Restoring the normal functioning of the affected eye will lead to normalization of color perception. Sometimes, for these purposes, it is necessary to resort to surgical intervention, as, for example, with cataracts.

If the cause of color blindness is medication, then there is no need to be particularly concerned about this. Usually, this phenomenon disappears after the drug with such a side effect is stopped. However, while taking the drug, you will still have to be careful when crossing the road at an intersection and especially railroad tracks.

Medicine is not yet able to cure congenital (hereditary) color blindness in women and men. But this does not mean that scientists do not pay due attention to this issue. It is just that drug treatment in case of color perception disorder is not relevant, and other methods are either considered insufficiently effective or are in the development stage.

For example, the use of genetic engineering techniques may in the future help solve the problem of color blindness by introducing missing color-sensitive receptor cells into the retina. But so far this method has not been used on humans, although experiments on monkeys have shown good results.

Attempts are being made to correct color vision using lenses made from a metal called neodymium. Glasses with lenses coated with a thin layer of neodymium help patients with reduced red or green color perception to better distinguish colors. However, wearing such glasses for other types of color blindness does not have significant results. In addition, special lenses distort the picture somewhat and reduce visual acuity.

In America, research has recently been conducted on multilayer glasses, which again contain neodymium. It is hoped that soon colorblind people will be able to see the world as people with normal vision see it. In the meantime, the following tips will help them correct their color perception and adapt to life:

• Color perception in people with reduced sensitivity to colors improves in the absence of bright light, which means you can try wearing glasses with wide frames or protective shields on both sides of the lenses.
• Those who have almost no color vision are advised to use darkened lenses of glasses, which are additionally equipped with protective shields on the sides. Dim light improves the work of sensitive cones.
• In the end, you can learn to live with your pathology, focusing not on color, but on the location of objects and the reactions of other people to them. Some nuances, such as traffic light signals, can be simply learned by heart, without delving into the color of individual signaling devices, but simply remembering their location.

Many people live without experiencing any particular discomfort due to color blindness until their attention is focused on it. It is possible to continue living normally if you do not dwell on your color blindness and compensate for the lack of color perception with memory and attention.

Prevention

Since color blindness in women and men can be congenital, and the culprit is a recessive gene passed down from generation to generation along the “mother-son” line, effective prevention in this case is not discussed. Color blindness or distorted color perception is just a physiologically conditioned feature that rarely manifests itself in the presence of a dominant gene of trichomatia (normal vision). And it is very difficult to fight what is inherent in nature itself.

The only thing that can be done is for future parents to be examined for color perception features before conceiving a child, for example, using the same Rabkin tables, which can even be found on the Internet. In this case, a woman and a man can predict in advance what is the probability of having children with normal vision.

But even if it turns out that the child may be color blind, this is not a reason to break up or give up the happiness of having a child. It is important to examine the child at the age of 3-4 years, when he or she will already begin to distinguish colors, which means that his or her color perception can be checked using Rabkin tables for children.

If it is discovered that the child perceives certain colors incorrectly, it is necessary to provide him with special attention and training that will help the baby navigate the world without relying on the colors of objects. The most important moments that ensure the child's safety (the same traffic light signals) will simply need to be learned together with the baby.

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Forecast

Color blindness in women caused by eye pathologies can be prevented if you treat your visual organ carefully and attentively, promptly treat eye diseases, and avoid injury. The prognosis in this case depends on the severity of the pathology and the effectiveness of its treatment, but in most cases it is favorable.