Forms and types of amblyopia
Amblyopia refers to the persistent reversible decrease in visual acuity of one or both eyes, which appears due to a functional disorder. Due to various eye diseases( astigmatism, strabismus, farsightedness, eye fundus pathology, clouding of the lens or cornea), information transmitted to the visual cortex of the brain is distorted, which leads to the disappearance of binocular vision. In this case, the brain, which can not build a clear three-dimensional image, excludes one eye from work, the visual acuity of this eye is markedly reduced.
Amblyopia is a fairly common disease, according to statistics it is diagnosed in 1-2 out of 100 people. Different types of amblyopia are diagnosed mainly in childhood, but sometimes adult patients accidentally or during a preventive examination find a decrease in vision on one eye.
Symptomatic and Degree of Disease
The main clinical manifestations of amblyopia are:
- Reduced visual acuity of one or both eyes
- Severe difference in visual acuity of right and left eyes
- Asymmetric eye reaction
- Muscle dysfunction of one or both eyeballs
Visual disturbances adults can feel onearly stages of the disease, the body subsequently becomes accustomed, and the person ceases to notice the signs of the disease and does not feel any discomfort.
This is important! Determining the presence of amblyopia is simple enough - it is only necessary to close your eyes in turns and, if you see one eye worse than others, you need to turn to an ophthalmologist.
Degrees of the disease
Depending on the loss of visual acuity, several degrees of amblyopia develop:
- Amblyopia of the 1st degree is called very weak amblyopia and is characterized by a decrease in visual acuity up to 0.9-0.8
- of the 2nd degree is a poor degree of development of the disease with visual acuity up to 0.7-0.5
- Amblyopia of the third degree - reduction of visual acuity to 0.4-0.3, characterizes the average amblyopia of
- IV degree - with a decrease in visual acuity from 0.2 to 0.05
- V degree is characterized by visual acuity below 0.05
The classification of amblyopia by the appearance time includes the primary and secondary form of the disease, and by prevalence - one-sided and two-sided amblyopia.
With primary( congenital) amblyopia throughout life, beginning with infant age, the visual acuity of one eye is lower than the other. This pathology is discovered in early childhood, either in adolescence or adulthood with a preventive examination by an ophthalmologist.
Doctors distinguish several reasons for the occurrence of congenital amblyopia:
- One of the reasons is the underdevelopment of the optic nerves in the prenatal period
- According to Koenigstein and Schleich, the cause of the development of the disease may be a retinal haemorrhage that the newborn can receive during the delivery process. It can be multiple point hemorrhages or one larger, more often such hematomas dissolve, but their consequence may be weakness of the retina, which has no ophthalmological signs.
- Genetically determined amblyopia may occur in children whose family has people suffering from this disease. Three ophthalmic diseases( amblyopia, anisometropia and strabismus) are genetically determined defects in the development of the visual apparatus, which are inherited.
In case the primary( congenital) amblyopia is diagnosed before the age of 6 and at an early stage, it can be cured. For treatment, pleoptics( active and passive) are used. Sealing( occlusion) of a healthy( leading) eye is called passive pleoptics. An active pleoptics is the combination of occlusion and the stimulation of the retina of the diseased eye, which is performed with the help of electric and light pulses, as well as special computer programs.
Secondary( acquired) amblyopia is the form of the disease in which it appears throughout life( both in childhood and adulthood) for various reasons. For reasons of development, several types of acquired amblyopia can be distinguished: deprivation( obscurant), anisometric, hysterical, disbinocular( refrobizmatic), refractive and mixed.
As factors in the development of secondary forms of amblyopia can be called:
- Cornea or lens opacity, which is not treated for a long time.
- Strabismus, more often it is the cause of secondary amblyopia in children. As a result of strabismus in the brain receives the wrong information, as a result of which he can not create a clear three-dimensional picture and excludes the sick eye from the work of the visual apparatus.
- Inadequate correction of visual acuity can cause mismatch of pictures from two eyes.
- An anomaly of cones causing color blindness is also a cause of the development of this pathology.
Secondary amblyopia forms
Deprivation( ambiguity) is called amblyopia due to visual deprivation of the eye, which is caused by congenital or acquired at an early age opacities of the optical environment of the eye( cataracts, opacity of the cornea), ptosis or hemophthalmia. After eliminating the pathology, the treatment of which is carried out by surgical methods, visual acuity usually remains reduced.
Strabismic or disbinocular amblyopia develops as a result of a disorder of binocular vision, which is caused by suppression of the eye for a long time. The cause of development is mostly strabismus, in which the brain perceives information from only one eye. Accordingly, the intensity of visual impulses arriving at the diseased eye is significantly reduced. Amblyopia, which develops in a child with a strabismus, leads to the fact that the sick eye deviates even more.
The method of treatment of strabismic amblyopia depends on the fixation by the eye of the object under consideration. Ophthalmologists distinguish dysbinocular amblyopia with different types of fixation:
- Amblyopia with correct( central) fixation - with this form of disease, the mowing eye, when turning off healthy, is able to fix the subject that is examining the central fossa of the yellow spot.
- Amblyopia with incorrect fixation( stable and unstable noncentral, as well as intermittent noncentral and central) - fixation of the examined object with a false macula.
- Amblyopia with no fixation.
Anisometric amblyopia arises due to a different refraction of the eyes, resulting in a difference in the magnitudes of the object under consideration displayed on the retina of the left and right eyes, which prevents the brain from forming a single visual image.
Refractive amblyopia can be said when the cause of the development of the disease becomes uncorrected refractive pathology, leading to fuzzy focusing of the object with one or two eyes.
Hysterical is called a rare amblyopia, arising against a background of affect or chronic stress. Psychogenic blindness may be the only manifestation of hysteria, or be combined with other disorders of the visual apparatus( violation of color perception, photophobia, narrowing of the field of vision).It is more common in women and is bilateral. The average duration of the disease is from 1 to 9 months. Cases of the disease stretched for several decades are described. The course of therapy includes sedatives, psychotherapy and even hypnosis sessions.
This is important! Remember, amblyopia is curable, with an early referral to a doctor and timely therapy, you have the opportunity to retain the ability to see the surrounding world in all its beauty.Like the article? Share with friends and acquaintances: