- Astigmatism - what is it?
- Astigmatism: Symptoms
- Ophthalmologist examination confirming astigmatism
- Astigmatism: everyday life
Astigmatism is one of the three most common eye disorders. The image seen by an astigmatist is blurry, blurry in different vision axes. This eye defect can be corrected with glasses or contact lenses. The laser also allows you to quit astigmatism once and for all. What are the symptoms of astigmatism and how is it treated?
Astigmatism - what is it?
In a properly built eye, light rays are focused on one point - on the retina. In astigmatism (or inaccuracy), the beam of rays entering the eye after refraction focuses on two points due to irregularities in curvature, causing a blurred image.
The irregular shape of the cornea, which in astigmatism is not a section of a ball but resembles that of a rugby ball, is responsible for 98% of cases of eye defects (the so-calledastigmatismcorneal). In a few cases, thiseye defectmay also be the result of an incorrect lens shape (so-called lenticular astigmatism), most often as a result of a congenital lens defect (e.g. in a small and spherical lens, in a cone or a spherical hump) front or rearlenses) .
Sometimes lenticular astigmatism develops as a result of cataracts. Generally speaking, in hyperopic astigmatism, both foci are outside the retina and in myopic astigmatism - in front of the retina. There is also mixed astigmatism, then one focus is in front of the other.
Astigmatism: Symptoms
Astigmatism is manifested by difficulties in focusing the visible objects (blurry vision from far and close), frontal headaches, squinting and rubbing the eyes, tilting the head. With mild astigmatism, the only symptom may be blinking more frequently, as people with this visual impairment try to get a sharp image through sudden changes in focal length.
A person suffering from astigmatism sees stars as spots, straight lines as curves. He cannot see both vertical and horizontal lines equally sharply (e.g. he sees only one arm of the cross more clearly). Contours are blurred, the sense of space may be disturbed. If in a small child - up to the age of 3 - severe astigmatism is not diagnosed and corrected, one or both eyes may be visually impaired.
ImportantLaser to help in the treatment of astigmatism
The following laser is used in the treatment of astigmatism: Lasik, Lasek, Epi-Lasik, and EBK - each method is corrected to 5D. The choice of the correction method is made, inter alia, based on the thickness and topography of the cornea. When the cornea is thin - the correction procedure can be completed with cross-linking. Laser correction involves shaping the cornea in the correct shape and modeling it, and very often, in the case of astigmatism, treatments are performed based on the topography of the cornea.
Ophthalmologist examination confirming astigmatism
You need to see an ophthalmologist to make sure you have astigmatism. The first tool to detect it was the keratoscope - invented by the Portuguese ophthalmologist A. Placido. It is a puck with alternating white and black circles. The examination consists in observing the shape of their reflections on the cornea.
The degree and axis of the eye inconsistency are measured by Jawal's ophthalmometer (keratometer). The most accurate method for determining astigmatism is computer videokeratography. It uses an image of a Placido disc thrown onto the surface of the cornea, which is recorded by a camera, and then transferred to a computer and analyzed. The test result is a color map of the cornea, a cross-section of the surface of the cornea, a map of digital values of the curvature of the cornea.
The last examination is necessary before the laser eye correction surgery. In everyday practice, an autorefractometer equipped with a keratograph is used. All these tests are painless and consist in observing the eye by an ophthalmologist using instruments.
Astigmatism: everyday life
Astigmatism interferes with everyday life, both in activities that require both far and close vision. Difficulties depend on the degree of the vision defect and whether it can be successfully corrected.
Lack or ineffective correction may cause ailments such as chronic conjunctivitis, eyelid margin inflammation or persistent headaches, greater fatigue when working at the computer, sometimes also reluctance to learn in children, and blurred vision and greater fatigue when driving a car - we do not see vehicle lights as spotlights, but more blurred.
Therefore, contact lenses and glasses correcting this eye defect must be carefully selected. Astigmatism can be corrected with glasses with cylindrical lenses or soft toric lenses, but when the surface of the cornea is significantly deformed (eg due to scars, diseases) or astigmatism is large - hard lenses.
If the ataxia is corneal, it can be treated with laser correction. If the origin of the defectit is lenticular and appeared, for example, as a result of a cataract, it disappears during cataract surgery, which consists in replacing the natural opaque lens with an artificial intraocular.
With a slight astigmatism (up to about 1 diopter), glasses are usually only worn for learning, driving a car, working at the computer. And almost every person has the so-called physiological astigmatism - up to approx. 0.5 diopters, because the correct cornea refracts more vertically than horizontally.
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