Astigmatism is a visual defect that causes distortion of the image and blurred vision. It must be corrected, otherwise it causes discomfort, can lead to severe visual impairment and even strabismus.
This is a visual defect that is caused by an irregular shape of the cornea of the eye, less often – a curved shape of the lens or the eyeball itself. Due to their irregular (oval, not round) shape, the picture is distorted – the light rays do not converge into focus on the retina, so an image of a blurry point instead of a clear one may appear on it. Also, vertical lines may appear blurry or out of focus.
As a rule, this is a congenital hereditary condition, often it progresses against the background of myopia or hyperopia. The acquired variant may occur due to injuries and surgeries that have formed scars on the cornea.
Symptoms of astigmatism are expressed in a fuzzy image and bifurcation of objects, in addition, the eyes get tired quickly, pain may appear in them and headaches occur. If the disease is not corrected, it can lead to a significant deterioration in vision, strabismus and a “lazy” eye, and affect the appearance.
These are special lenses that are used to correct astigmatism.
Astigmatism can accompany other visual defects, for example, combined with nearsightedness or farsightedness. In this case, wearing conventional spherical lenses does not completely solve the problem. The disease remains uncorrected, the image is still blurry, unpleasant accompanying symptoms continue to bother, and vision may deteriorate.
Often, with a complex and neglected form, glasses are not suitable, because they cause pain in the eyes and dizziness. Toric contact lenses are a more modern and practical way of correction. They are selected individually. Moreover, you can choose an option that corrects two diseases at once: astigmatism and myopia or hyperopia. It is also possible to correct astigmatism with laser surgery, as prescribed by a doctor.
Unlike ordinary spherical lenses, astigmatic lenses have a different shape – spherical-cylindrical. It, as well as bulges on the surface, different vertical and horizontal optical powers correct the focus of the light rays on the retina and make the image clear and sharp.
Because of these features, additional parameters of the lens are important: axis and cylinder. They must be listed in the medical prescription. It is better that the check is carried out by an experienced contactologist, since the selection of corrective means is more difficult than usual.
In order for an astigmatic lens to provide clear vision in different conditions, with eye movement, head rotation, physical activity, its position must stabilize on the eye, that is, it must constantly maintain the correct orientation. A conventional medical lens can hold smoothly and move freely because it is optically symmetrical. Toric is optically asymmetric, having different optical power vertically and horizontally.
The best result is given by dynamic stabilization methods, when the correct position of the lens is ensured by holding it for centuries, while blinking. There are also gravitational methods, when the contact lens is thickened to the lower edge and it constantly occupies a vertical position due to the action of gravity. However, this does not provide correct orientation in all head positions. You can find stabilization that combines both methods.
A slight astigmatism in newborns is considered the norm, but in children over 1 year old this is already a deviation. Therefore, at this age and beyond, it is necessary to regularly check the eyesight of children for the timely detection of defects. It must be corrected to avoid consequences ranging from reduced visual acuity to strabismus and amblyopia (“lazy eye”).
A mild degree of astigmatism up to 0.5 diopters is common and may not need correction if there are no complaints. However, if the activity involves regular eye strain, such as working at a computer for a long time, then it is better to protect your eyes and wear glasses or lenses.
As a rule, you can buy astigmatic lenses in online contact lens stores or optics stores. Also ask about the possibility of bringing them to order, since with difficult vision the necessary ones may not be in constant stock, but the seller will not have any problems bringing them for you.