Congenital glaucoma – is more often the hereditary disease which is followed by gradual increase in intraocular pressure and the accompanying visual violations caused by it. Refer increase in the sizes of eyes to the main symptoms of this pathology (at babies), morbidity which leads to concern and tearfulness of the child, a photophobia, a miopiya or an astigmatism. Diagnosis of congenital glaucoma is made on the basis of data of ophthalmologic survey, studying of the hereditary anamnesis of the patient and the course of pregnancy, genetic researches. Treatment only surgical, and it has to be executed as it is possible before development of irreversible secondary violations in an organ of vision earlier.
Congenital glaucoma – genetic, is more rare - the disease acquired vnutriutrobno which is characterized by an underdevelopment of a corner of the forward camera of an eye and trabekulyarny network that finally leads to increase in intraocular pressure. This state is considered in ophthalmology rather rare and meets approximately in one case on 10000 childbirth. Some researchers believe that this statistics not absolutely correctly reflects reality, some forms of congenital glaucoma can not prove up to teenage age. In spite of the fact that pathology is inherited on the autosomno-recessive mechanism, among patients boys prevail a little – sexual distribution makes about 3:2. On age of development of the main symptoms, and also existence or lack of genetic defects allocate several clinical forms of this disease. Importance of timely detection of congenital glaucoma is caused by the fact that without the carried-out treatment the child can go blind in 4-5 years after development of the first displays of pathology.
Reasons of congenital glaucoma
The vast majority of cases of congenital glaucoma (not less than 80%) are followed by a mutation of a gene of CYP1B1 which is localized on the 2nd chromosome. It codes protein P4501B1 cytochrome which functions are studied insufficiently for today. It is supposed that this protein somehow participates in synthesis and destruction of alarm molecules which take part in formation of trabekulyarny network of the forward camera of an eye. Defects of structure of P4501B1 cytochrome lead to the fact that metabolism of the above-stated connections becomes abnormal, as promotes violation of formation of an eye and development of congenital glaucoma. Now it is known more than fifty kinds of mutations of a gene of CYP1B1 which are authentically connected with development of this disease to reveal however the interrelation between concrete defects of a gene and certain clinical forms did not work well yet.
In addition, there are instructions for a role in development of congenital glaucoma of other gene – MYOC located on the 1st chromosome. The product of its expression, a protein under the name , is widely presented in eye fabrics and too participates in formation and functioning of trabekulyarny network of an eye. Earlier it was known that mutations of this gene are the reason of open-angle juvenile glaucoma, however at simultaneous damage of MYOC and CYP1B1 the congenital kind of this pathology develops. Some researchers in the field of genetics believe that detection of a mutation of a gene of a miotsillin against the background of defect of CYP1B1 does not play a special clinical role in development of congenital glaucoma and is just coincidence. Mutations of these both genes are inherited on the autosomno-recessive mechanism.
Except hereditary forms of this pathology approximately in 20% of cases congenital glaucoma at absence is diagnosed, both cases, and pathological genes for parents. In that case either spontaneous mutations, or damage of tissues of eye to the pre-natal period can act as the reason of development of eye violations. The last can be caused by infection of mother during pregnancy with some infections (for example, toxoplasmosis, a rubella), pre-natal injuries of a fruit, a retinoblastoma, influence of teratogenny factors. As in such situation there is no genetic defect, such pathology carries the name of secondary congenital glaucoma. Besides, similar violations of an organ of vision can take place at some other congenital diseases (Marfan's syndrome, and others).
Whatever was the reason of congenital glaucoma, the mechanism of development of violations at this state is almost identical. Because of an underdevelopment of a corner of the forward camera of an eye and trabekulyarny network watery moisture cannot normally leave a cavity, there is its accumulation that is followed by gradual increase in intraocular pressure. Feature of congenital glaucoma is the fact that fabrics skler and corneas at children have bigger elasticity, than at adults therefore at accumulation of moisture there is an increase in the sizes of an eyeball (most often two at once, it is very rare only one). These are reduces intraocular pressure, however a little over time and this mechanism becomes insufficient. There is a flattening of a crystalline lens and cornea, on the last there can be microgaps leading to turbidity; the disk of an optic nerve is damaged, the retina becomes thinner. Finally there can be its peeling – turbidity of a cornea and otsloyka of a mesh cover of an eye are the leading reasons of a blindness at congenital glaucoma.
Classification of congenital glaucoma
In clinical practice congenital glaucoma is divided first of all into three versions – primary, secondary and combined. Primary it is caused by genetic disorders, it is inherited on the autosomno-recessive mechanism and makes about 80% of all cases. The reason of secondary congenital glaucoma consists in pre-natal violation of formation of organs of vision of various not genetic nature. The combined version, as appears from the name, is followed by existence of congenital glaucoma against the background of other hereditary diseases and states. Primary form caused by genetic defects in turn is subdivided into three clinical forms:
- Early congenital glaucoma – at this form symptoms of a disease come to light at the birth, or they are shown in the first three years of life of the child.
- Infantile congenital glaucoma – develops at the age of 3-10 years, its clinical current is already poorly similar to early type and approaches that at adults at other forms of glaucoma.
- Juvenile congenital glaucoma – the first manifestations of this form of a disease are registered most often at teenage age, the symptomatology is very similar to infantile type of pathology.
Such considerable scattering at the age of development of congenital glaucoma is directly connected with degree of an underdevelopment of trabekulyarny network of an eye. What more expressed violations in these structures, accumulation of watery moisture with increase in intraocular pressure begins that earlier. If the underdevelopment of a corner of the forward camera of an eye does not reach considerable sizes, then in the first years of life of the child outflow happens quite normally, and violations develop much later. Attempts to connect certain clinical forms of congenital glaucoma with concrete types of mutations of a gene CYP1B1 were not crowned with success today, and mechanisms of development of this or that type of a disease are still unknown.
Symptoms of congenital glaucoma
The most peculiar manifestations characterize an early form of primary congenital glaucoma that is caused by anatomic features of a structure of an eye at the child aged up to 3 years. Seldom or never glaukomny changes can be noticed already at the birth, most often in the first 2-3 months of life the disease proves nothing. Then the child becomes uneasy, sleeps badly, very often is capricious – it is caused by unpleasant and painful feelings from which congenital glaucoma debuts. In several weeks or months slow increase in the sizes of eyeballs begins (more rare - one). Skler can lead increase in intraocular pressure and elasticity of fabrics to significant increase in eyes that externally makes a false impression of the beautiful "big-eyed" child. Then hypostasis, a photophobia, dacryagogue joins these symptoms, sometimes there is a turbidity of a cornea.
Infantile and juvenile forms of congenital glaucoma are in many respects very similar, only the age of development of the first displays of a disease differs. Increase in the sizes of eyeballs at the same time, as a rule, does not happen, pathology begins with feeling of discomfort and morbidity in eyes, headaches. The child can complain of deterioration in sight (emergence of bright auras around light sources, "midge" before eyes). These types of congenital glaucoma often are followed by other violations of the visual device – squint, an astigmatism, a miopiya. Over time there is a narrowing of a field of vision (an opportunity to see objects side sight is lost), violation of dark adaptation. The photophobia, hypostasis and an injetsirovaniye of vessels the skler characteristic of an early form of a disease, at these forms most often are not observed. In the absence of treatment any kind of congenital glaucoma leads to a blindness because of an otsloyka of a retina or an atrophy of an optic nerve over time.
Diagnosis of congenital glaucoma
Detection of congenital glaucoma is made by the ophthalmologist on the basis of the given survey, ophthalmologic researches (a tonometriya, a gonioskopiya, a keratometriya, biomicroscopy, an oftalmoskopiya, BONDS biometrics). Also important role in diagnostics of this state is played by genetic researches, studying of the hereditary anamnesis and the course of pregnancy. At survey are found increased (at an early form) or the normal sizes of eyes, hypostasis of the fabrics surrounding an eyeball can be also observed. Horizontal diameter of a cornea is increased, on it microgaps and turbidity are possible, sclero it is thinned and has a bluish shade, is surprised at congenital glaucoma and an iris of the eye – in it there are atrophic processes, the pupil inertly reacts to light irritants. The forward camera of an eye is deepened (1,5-2 times more than age norm).
At an eye bottom the long time does not arise any pathological changes as due to increase in the sizes of an eyeball intraocular pressure first does not reach considerable sizes. But then quickly enough excavation of a disk of an optic nerve develops, however at pressure decrease expressiveness of this phenomenon also decreases. At congenital glaucoma thinning of a retina is of increase in the sizes of eyes the result that in the absence of treatment can lead to its gap and a regmatogenny otsloyka. Often against the background of such changes the miopiya is found. Tonometriya shows some increase in intraocular pressure, however this indicator should be compared with the front-back size of an eye as stretching skler smoothes VGD indicators.
Studying of the hereditary anamnesis can reveal similar changes at the patient's relatives, at the same time quite often it is possible to define autosomno-recessive type of inheritance – it testifies in favor of primary congenital glaucoma. Existence in the course of pregnancy of infectious diseases of mother, injuries, influences of teratogenny factors indicates a possibility of development of a secondary form of a disease. Genetic diagnostics is performed by means of a direct sekvenirovaniye of the sequence of a gene of CYP1B1 that allows to reveal its mutations. Thus, only the doctor geneticist definitively can prove existence of primary congenital glaucoma. Besides, in the presence of such state at one of parents or their relatives it is possible to run for search of a pathological form of a gene before conception or prenatal diagnostics by amniocentesis or other techniques.
Treatment and forecast of congenital glaucoma
Treatment of congenital glaucoma only surgical, is possible use of modern laser technologies. Conservative therapy with use of traditional means (a drop pilocarpine, a clonidine, , ) is auxiliary and some time can be used during operation expectation. Surgical intervention comes down to formation of a way of outflow of watery moisture that reduces intraocular pressure and eliminates congenital glaucoma. The method and the scheme of carrying out operation is chosen in each case strictly individually. Depending on a clinical picture and features of a structure of an eyeball the goniotomiya, a sinustrabekulektomiya, drainage operations, laser cyclophotocoagulation or cyclocryocoagulation can be carried out.
The forecast of congenital glaucoma at timely diagnostics and carrying out operation most often favorable if treatment is made with delay, sight violations, various on expressiveness, are possible. After elimination of glaucoma not less than three months of dispensary observation at the ophthalmologist are necessary.