Anophthalmia: when you can not see the world with your own eyes
Last reviewed: 23.04.2024
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The eyes are not accidentally called the mirror of the soul, because they are a reflection of how we perceive the world. And we perceive it with the help of the senses, among which the paired organ of vision occupies one of the leading places. Lack of eyes (anophthalmia) is a big problem affecting the entire future life of a child born with a developmental defect that cannot be corrected. Staying blind from birth to the end of his difficult life, a person with anophthalmos will not know what he, his family or other people look like. In addition, the aesthetic side of such a defect raises great doubts as to what is the reason for addressing surgeons.
Anophthalmia problem
The absence of our usual organs in a person always causes some confusion and even uncontrollable dislike, which, mixed with pity, forms an inexplicable feeling in words. It is experienced by those who have had to face the misfortune of another person, while the patients themselves at a conscious age instinctively feel such an ambivalent attitude that it is very difficult psychologically.
But anophthalmia is not only a psychological and cosmetic, but also a medical problem, because we are talking about the head and the part of it that is primarily paid attention to. In the guise of a person everything should be in its place, otherwise secondary defects may occur. In the case of congenital anophthalmia, this is an abnormal, disproportionate formation of the bones of the facial skeleton, which requires early surgical intervention. True, the restoration of vision in the absence of the eyeball and other organs responsible for the visual perception of the world is not at all.
It must be said that children with a defect such as the absence of one or two eyes (one-sided and two-sided anophthalmia) are born quite rarely. Statistics says only about 3-10 episodes per 100 thousand babies. At the same time, the appearance of newborns does not differ from normal children with closed eyes. Lack of eyeballs can be noticed when the child opens his eyes.
Causes of the anophthalmia
Based on the fact that the congenital absence of the eyeballs is a hereditary disease caused by a mutation of the gene responsible for the development of the organs of vision, it is very difficult to determine the true causes of the development of the disease. Parents may not even suspect that there is a pathological gene in their chromosome set. The reduced size of the eyeballs, which is not considered a major physiological or cosmetic defect, already implies the presence of a recessive gene, but it is simply impossible to predict whether it will be transferred to a child from both parents.
Another thing is that congenital anophthalmia can have two forms: the true one, the cause of which is precisely the child’s getting 2 pathological genes, and the imaginary one, when other factors influenced the development of the fetal organs of vision. In this case, any negative effect on the fetus in the first trimester of pregnancy, when the rudiments of virtually all human organs and systems are formed, can be considered risk factors for impaired eye development.
Of particular danger are infections that, through the mother’s blood, can reach the fetus, affecting its development. In women whose children were born with imaginary anophthalmia, during the period of gestation, rubella, measles and shingles were most often diagnosed.
As a risk factor, it is also possible to consider the toxic effect on the fetus of environmental factors or the presence in the uterus of amniotic banners (connective tissue threads stretched between the two walls of the uterus). In the latter case, compression of individual parts of the body of the fetus takes place, which can cause deformations of the facial skeleton and underdevelopment of the organs of vision.
Imaginary anophthalmia rarely occurs as a separate disease. It is usually one of the symptoms of various congenital syndromes (for example, Lenz syndrome inherited in an X-linked recessive manner).
Acquired anophthalmia is the absence of one, less often two eyeballs as a result of amputation. The cause may be injuries and severe infections of the eye, when its tissues have to be removed to prevent the spread of infection to the brain area. In some cases, eye removal is resorted to due to the presence of a tumor.
Pathogenesis
Unusual pathology has quite understandable reasons, which, however, does not inspire optimism. The fact is that by studying the pathogenesis of anophthalmia, scientists have identified one important internal factor affecting the development of the organs of vision in the prenatal period. This factor is specific genes, one of which is responsible for the normal development of the organ of vision, and the other for its absence.
A gene is a segment of a DNA molecule that carries information about the structure of a protein, from which certain cells and cellular structures are formed. That is, it is a unit of hereditary material that is responsible for the formation of a certain function or attribute that is transferred to other generations. Thus, genetic pathologies are hereditary health disorders.
Anophthalmia, or the absence of eyeballs, is a hereditary disease that is extremely unlikely to be passed on to the next generation. The fact is that in genetics there is such a thing as "alleles". These are different variants of the same gene, which can be passed on to offspring with different probability.
Chromosomes are structures that contain tens and hundreds of thousands of genes, which are a kind of scheme or instruction for the body’s work. A human child receives 2 sets of chromosomes from parents. One set contains 23 chromosomes. The second set is considered to be similar to the first, i.e. Chromosomes labeled with the same number are responsible for the formation of cells and the functions of the same structures. It turns out that we receive from parents not one, but two homologous (with the same functions) genes.
By obtaining a double set of chromosomes, we are able to obtain one of two variants of the same gene. As a rule, one of the variants of the gene is stronger, i.e. Is manifested regardless of the presence in the genome (a set of genes in a single set of chromosomes) of another allele of this gene. Such a gene and the trait caused by it is called dominant. Receiving at least one such gene from parents, with a high degree of probability, we get exactly this trait, and not the one that may be due to the second allele.
Weaker genes are called recessive. In combination with the dominant allele, they rarely show their properties. Only those who received 2 recessive genes from their parents are more likely to get a recessive trait.
Anophthalmia, like Wilson's disease, characterized by a violation of the exchange of copper in the body with severe impairments of the nervous system, the liver, the digestive system, is inherited in an autosomal recessive manner, i.e. A person exhibits recessive traits, which are obtained along with the corresponding genes. Such an outcome is more likely if the child receives from the parents 2 identical recessive variants of the same gene.
Those people who receive 2 identical alleles of a gene from their parents are called homozygous. If there are 2 different variants of the same gene in a double set of human chromosomes, it is called heterozygous for this gene.
In genetics tasks, dominant genes are usually denoted by capital letters, and recessive genes by small letters. For example, if a child receives from one parent a rare recessive gene (denoted by “a”), which causes anophthalmia (abnormal development of the eyes), and from the second — the dominant allele of this gene (denoted by “A”), the likelihood of anophthalmos development will be very low
In a homozygous organism that received two recessive genes from parents, this probability will be 100%. But what is the probability of having a child with anophthalmia in parents, one of whom has this disease or both contain a recessive gene in the genome?
We receive from parents a set of 2 identical genes, but their combination may be different: AA, aa, Aa. In the first case, the disease definitely does not develop, in the second - vice versa. In heterozygotes, as genetics have found out, there is only a decrease in the eyeballs, while the probability of obtaining just such a set of genes is 50%.
The remaining 50% of children will be homozygous, i.e. With a set of 2 identical alleles of the same gene: AA or aa. It turns out that the probability of anophthalmia is 25%, i.e. The disease is diagnosed in every fourth child in the family in question.
It is clear that the absence of a pathological gene “a” in one of the parents reduces the likelihood of anophthalmia to zero. This explains the small number of newborns without eyeballs.
Symptoms of the anophthalmia
We have already mentioned that congenital anophthalmia can be true or imaginary, while the external symptoms of the disease do not differ much. In the true form of the disease, the cause of which is the inheritance of pathological genes, the absence of both eyes is usually observed (bilateral anophthalmia), because if one of the obtained genes carries information about the normal development of the organ of vision, the child’s eyeballs will develop, but will be smaller.
In addition to the eyeballs, children with anophthalmos do not have other eye tissues that form our organ of vision, give it the opportunity to move inside the orbit, to focus on nearby and distant objects.
For the imaginary anophthalmia is characterized by the absence of only the eyeball, while the other components of the eye are present, but remain underdeveloped. In this case, with the same probability can be affected both eyes. In this case, along with bilateral absence of eyes, there are children in whom anophthalmia is observed on the right (no right eye) or on the left (no left eye). In this case, the absence of one of the eyes is compensated by an increase in the visual acuity of the second.
With bilateral anophthalmia, the child remains blind for life, because the prosthesis helps to solve only the aesthetic side of the problem and correct the further development of the facial skeleton.
Externally, newborns with anophthalmia practically do not differ from sleeping normally developing children. On the face they have eye slits, but various deformities of the eyelid are possible (the first, although non-specific signs of developmental pathology). Defect in the form of the absence of eyeballs becomes noticeable when the child opens his eyes.
At the same time, it is almost impossible to notice a genetic abnormality on ultrasound, which can be performed more than once during pregnancy. For parents, the birth of a baby without eyes becomes a sad surprise, while the child himself doesn’t even suspect his defect for a long time, because in the womb of his mother he didn’t need vision.
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Complications and consequences
The absence of one or two eyes is a tragedy that leaves an imprint on the further development of the child. From a medical point of view, the only complication of the pathology that arose in the early periods of a child’s life may be a violation of the formation of the facial skeleton, which makes a person’s appearance even more repulsive and may affect the functioning of nearby organs.
In fact, the problem is much more extensive. Although modern society has noticeably changed its attitude towards people with developmental defects and has ceased to reject them, yet a certain shade of hostility towards them remains for many, This cannot but affect the patient’s mental and emotional state, causing a decrease in self-esteem, negativity in response to showing pity., isolation, etc.
True, the appearance of a person with anophthalmos can be corrected through surgery. Another thing is that the operation will not return the child's vision, and in the absence of both eyes, cognitive activity, and hence the general psychophysical development will noticeably lag behind the norm.
Children with anophthalmia are forced to study in special educational institutions in order to gain at least an elementary understanding of the world around them, learn to read and write using special methods, and acquire certain self-service skills. However, they remain for the rest of their lives visually impaired with a limited choice of professional activity.
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Diagnostics of the anophthalmia
The fact that ultrasound diagnosis cannot be done in the prenatal period allows the doctors to make the eyes of the field of birth of the child when the defect becomes visible from the side. The absence of eyeballs is difficult to hide, even with closed eyelids, not to mention the fact that after birth the doctors examine the child and check the reaction of the eye to light.
True, the clinical picture obtained by an external examination does not provide sufficient information about the causes and forms of anophthalmia, and standard tests do not help in any way to advance in this regard. To the aid comes instrumental diagnostics, namely x-ray examination or computed tomogram of the skull.
In true anophthalmia, in addition to the eyeballs, there are also no other tissues of the organ of vision (optic nerve, chiasm or chiasm, external articular body), which are histologically determined, and even the aperture in the bones of the skull, which indicates the complete absence of the eye germ. The appendages of the eyes of these newborns are preserved, but have reduced size, the orbit and the cavity of the conjunctiva are small.
The eyelids are usually small, often deformed, which can be seen even with the naked eye. The small size of the palpebral fissure and conjunctiva is also visually determined.
Most often, this pathology is combined with a general underdevelopment of the frontal regions of the brain and impaired formation of the visual divisions of the nervous system. These children are prescribed additional studies to determine the depth of the defect.
An imaginary anophthalmia is characterized by the presence of a hole and a rudimentary eye is found in the depth of the orbit in the form of a small seal, which is detected by means of echography. This again confirms the fact that the organ of vision was formed, but stopped in the development at some stage of the intrauterine life of the child.
X-ray and histological studies play a large role in the differential diagnosis, helping to understand the mechanism of the disease and determine its shape. Moreover, the disease also needs to be differentiated from microphthalmia, i.e. Underdevelopment of the eye, enophthalmia (deep landing of the eye) and some other malformations of the organ of vision.
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Treatment of the anophthalmia
When a child is born in a family without one or two eyes, the parents have a natural question: what to do next? The appearance of the child and possible complications, which can be avoided, can become an obstacle in his future life, affect relationships with other people, complicate entry into society.
In order to somehow reduce the negative effects of anophthalmia at an early age, prosthetics are used in combination with the use of antiseptics that do not come into contact with the material of the prosthesis. The fact is that the skeleton and bones of the baby's skull continue to grow even after the birth of a child, therefore, the earlier the prosthesis is installed, the less likely the deformity is.
But the growth of the bones of the skull is also the cause of repeated operations, during which the existing prosthesis is replaced with another, somewhat larger size. Any operation, including prosthetics, is a trauma for the children's body, therefore, multiple surgeries are considered undesirable.
An important achievement of modern medicine is the possibility of injection treatment, which in childhood replaces prosthetics. While the child is small and his bones are growing, a non-invasive technique is used - the introduction of gualuronic acid into the orbit tissue, which prevents the abnormal development of the orbital tissues, prevents the development of asymmetry of the face with unilateral anophthalmia.
Such a safe treatment is possible from the first days of a child’s life. The procedure is carried out in an outpatient clinic under local anesthesia, without delivering much discomfort to the baby. The prosthesis is installed later, when the period of growth of the facial skeleton is over.
If it is impossible to perform prosthetics over the age of 7 years, an operation is performed to increase the palpebral fissure (external cantomy), after which it becomes possible to use a prosthesis or implant. Alas, due to the risk of deformity of the eyelids after surgery, such surgical intervention itself may be the reason for the impossibility of prosthetics in the future.
Prevention
True anophthalmia is considered a genetic disease, the causes of which remain a mystery (it is difficult to say why a pathological gene appears and predict its transmission to offspring). Prevent such a disease is almost impossible, except to carefully select the sexual partner, studying the entire history of applicants. But this must be done at the planning stage of pregnancy. At risk are those who have already experienced anophthalmia or microphthalmia, which develops if a single recessive gene has been passed on to the child.
But the development of the imaginary form of pathology can be avoided even before the birth of the child. Prevention consists in the prevention of infectious diseases (especially in early pregnancy), regular ultrasound examinations, which reveal strands in the uterus, and avoidance of poisonous and toxic substances on the body of a pregnant woman.
Acquired anophthalmia is most often the result of a person’s carelessness or careless attitude towards their health. By avoiding eye injuries and promptly turning to an ophthalmologist about diseases of the organ of vision, you can save what is given to us at birth, for life, enjoying the opportunity to visually perceive the world as it really is.
Forecast
Anophthalmia - a disease in which there is an uncorrectable lack of vision. The prosthesis can create the appearance of a normal eye, giving the appearance of the child a familiar look, but it is not possible to restore the sight.
The prognosis of the development of a child with congenital anophthalmia depends on the form of the pathology (bilateral or one-sided), as well as the assistance that adults will provide to the child (parents, educators, teachers). As for life in general, everything depends on comorbidities and malformations, because this pathology is often only one of the symptoms of complex health disorders.