Astigmatism at children – the refraction violation of sight which is followed by change of sphericity of a cornea or crystalline lens and their refracting properties. The astigmatism can cause decrease in sight, dizziness, a migrenepodobny headache, squint in children. Diagnostics of an astigmatism demands inspection of children by the ophthalmologist: carrying out a skiaskopiya, autorefractometry, definition of degree of an astigmatism by means of cylindrical lenses, a keratometriya, computer topography of a cornea, visual acuity check, etc. For correction of an astigmatism at children glasses wearing or contact lenses, OK - therapy is appointed.
Astigmatism at children
Astigmatism at children – the defect of the refracting eye environments leading to an illegibility, blurring of the image of a visible object. The term "astigmatism" in literal translation from Latin means "lack of a point of focus". At an astigmatism at children as a result of the wrong curvature of a cornea (is more rare than a crystalline lens) the beams proceeding from one point cannot gather in one focus again on a retina therefore the image of a subject appears unsharp and indistinct. The astigmatism of this or that degree occurs practically at each child, however his small degree (less than 1 ) which is not influencing visual acuity is characteristic of 90% of children. At the same time, the astigmatism demands special ophthalmologic correction from 10% of children. The astigmatism at children often is followed by short-sightedness or far-sightedness.
The astigmatism reasons at children
In most cases the astigmatism at children has hereditary character and is predetermined genetically. In this case at the child congenital violation of sphericity of a cornea or crystalline lens takes place. The astigmatism of high degree at children can accompany albinism, a congenital pigmentary retinit, an alcoholic syndrome of a fruit.
The acquired astigmatism occurs at children at cornea hems, the undergone operations and injuries of an eye, the crystalline lens incomplete dislocation which is followed by a rupture of a tsinnovy sheaf. Quite often the astigmatism at children develops owing to pathology of the zubochelyustny system causing deformation of walls of an eye-socket. At an astigmatism at children associated diseases of eyes can come to light: , congenital , , hypoplasia of an optic nerve.
As immediate cause of an astigmatism at children serves violation of sphericity of a cornea or is more rare – the wrong curvature of a crystalline lens. Therefore light beams after refraction in optical environments dissipate and create on a retina at the same time several focuses. In that case the child sees objects in a wrong way and indistinctly. Over time the astigmatism at children leads to secondary decrease in visual acuity and development of an ambliopiya.
Classification of an astigmatism at children
Children can have a physiological astigmatism or pathological. The physiological astigmatism at children is characterized by a difference in refraction of two main meridians less than 1 ; does not affect visual acuity and does not demand treatment. Emergence of a physiological astigmatism is connected with the uneven growth of an eyeball at children. In case of a pathological astigmatism at children the difference in refraction exceeds 1 therefore is followed by decrease in sight.
Also in children's ophthalmology distinguish the correct and wrong astigmatism. At the same time children can have the correct astigmatism of several types:
- simple gipermetropichesky – with a normal refraction of one main meridian and gipermetropichesky – another;
- simple miopichesky - with a normal refraction of one main meridian and miopichesky – another;
- difficult gipermetropichesky – with a gipermetropichesky refraction of both main meridians, but expressed in various degree;
- difficult miopichesky - with a miopichesky refraction of both main meridians, but expressed in various degree;
- mixed – with a miopiya in one meridian and a gipermetropiya – in another.
The following signs are characteristic of the wrong astigmatism at children: spasmodic, but not smooth transition of a refraction from one main meridian to another; not perpendicularity of the main meridians relatively each other; various refraction of different sites of one meridian.
About astigmatism degree at children judge by a refraction difference in both main meridians. On the basis of it allocate 3 degrees of an astigmatism at children: weak (less than 1 ), average (from 3 to 6 ) and high (over 6 ).
Astigmatism symptoms at children
The astigmatism can arise at children of any age. Parents can suspect an astigmatism at the child in case notice that it inclines the head or blinks eyes, examining the image; often stumbles or stumbles when walking, touches furniture corners, puts objects by a table, hardly focuses a look on the printing text, delays a finger an external corner of an eye.
Children with an astigmatism can complain of a sight illegibility, bad vision of objects close or in the distance, distortion of visible objects, feelings of visual discomfort, visual fatigue, fatigue and irritation of eyes, a headache in connection with visual loading, doubling in eyes. The Nekorrigirovanny astigmatism at children can lead to an arrest of development of visual system in general and to developing of squint and an ambliopiya.
As children well adapt to deterioration in sight, subjective signs of violation of a refraction can not be. In this regard the special role in identification of an astigmatism at children belongs to dispensary surveys of the child by the children's ophthalmologist.
Diagnostics of an astigmatism at children
Most often the astigmatism is diagnosed at inspection of children of the second year of life. At an astigmatism at children carrying out complex assessment a condition of eyes and visual function is necessary.
The diagnostic algorithm includes carrying out a vizometriya, the biomicroscopy, an oftalmoskopiya, ultrasonography of an eye and ophthalmometry allowing to reveal the accompanying pathology of an eye and a probable cause of an astigmatism at children. Assessment of a refraction is made by performance of shadow test (skiaskopiya) with spherical or cylindrical lenses, autorefractometry, a keratometriya, a computer keratotopografiya.
As a result of full inspection the ophthalmologist defines presence, degree and a form of an astigmatism at children.
Treatment of an astigmatism at children
Correction of an astigmatism at children is carried out by conservative methods. Carrying out refraction operations (laser correction of an astigmatism, a keratotomy, etc.) is recommended after 18-20 years when the visual system is already completely created.
At the astigmatism of weak degree which is not complicated by a gipermetropiya or a miopiya, and also subjective symptoms, correction usually is not required. In other cases selection of points or contact lenses is shown to children with an astigmatism.
For correction of a simple astigmatism at children cylindrical lenses are used; for correction difficult and mixed - the sferotsilindrichesky lenses combining in themselves spherical and cylindrical glass. As an optimum method of correction of an astigmatism of any kind serves the contact correction promoting more accurate focusing of the image on a retina. Contact lenses demand the careful address and special leaving that limits their application for children of younger age.
One of ways of correction of an astigmatism at children is the ortokeratologiya meaning carrying the rigid contact lenses which are temporarily correcting curvature of a cornea. OK - lenses are put on only for the night, for a dream and suit the children who are refusing flatly to wear glasses or contact lenses. Ortokeratoterapiya is applied at an astigmatism at children not higher than 1,5 .
Parents have to know that points and contact lenses do not cure, and only correct an astigmatism at children, improving visual function. Completely it is possible to get rid of an astigmatism only by means of surgical intervention.
The forecast and prevention of an astigmatism at children
Degree of a congenital astigmatism tends to decrease within 1 year of life. At the most part of children to 7-year age degree of an astigmatism is stabilized. In the absence of correction both reduction, and increase in degree of an astigmatism is possible with age. In due time undertaken correction of an astigmatism at children promotes increase in visual acuity, a possibility of reduction of force of glasses or full refusal of glasses wearing. At the astigmatism of high degrees which is not exposed to ophthalmologic correction refraction squint and an ambliopiya can develop.
Children with an astigmatism have to be observed at the oculist and undergo planned inspection twice a year. As children have a constant growth of an eye, it is necessary to monitor timely change of optics.
Decrease in risk of emergence of an astigmatism at children requires alternation of zritelyyony loadings with gymnastics for eyes, mobile rest. Occupations swimming, a contrast shower, massage cervical zones, good nutrition are useful.