This ailment appears when the eye sees an unclear picture, which arises from a resulting irregular focusing of the light rays upon the retina. This results from the irregular curvature of the cornea and lenses, which can be controlled through proper glasses or laser procedure. Laser correction, which can be performed in our clinic, has the goal of adjusting the curvature of the cornea, which prompts the light wave to return its focus at the proper point.
If we visit the ophthalmologist because of unclear vision, both near and far, we will most often hear the diagnosis of astigmatism. Astigmatism is not an eye disease, but a vision defect resulting from this, the optical system of the eye is not able to properly focus the light rays on the retina. Parallel light rays refract on two different levels (i.e. vertical and horizontal), which causes an unclear image, which is curving and waving and with poor contrast. Colloquially speaking, astigmatism continually feels like it is to be out: straight lines are undulating, despite their sincere intentions, they are unable to focus, and have a sense of a space disorder. This blurred vision hinders daily activity.
Estimates state, that about 40% of the population has a defected shaped cornea or lens, and beyond this comes the symptoms of astigmatism. You cannot avoid these- the defect is an inherited trait and our lifestyle does not have the slightest influence over its growth. Nearly 50% of the patients diagnosed with astigmatism experience such a pronounced impairment of vision quality and the associated discomfort daily, that they require ophthalmologic help. In uncomplicated cases, glasses with cylindrical lenses or toric contact lenses. In more difficult cases, it is worth undergoing laser correction for astigmatism, i.e. FemtoLASIK method, implant of Phakic lenses or lens replacement surgery.
Symptoms may suggest the presence of astigmatism
Besides unfocused vision, both from far and from near, astigmatism manifests itself with other ailments related to the fact, that the patient continually squints and rubs his eyes, in order to correct his vision quality. So there appears:
- burning in the eye,
- recurring conjunctivitis,
- sensation of dizziness,
- sense of vision impairment,
- quick fatigue when performing tasks that include visual concentration, i.e. while working on a computer or driving a car.
As often as an adult immediately seeks the help of an ophthalmologist, much time often passes before a child will seek help. Before we can confirm that a headache, lack of desire to read or a problem with coordinated movement, without knowing the background neurologically or psychologically, are connected to vision problems. That is why we conduct preventive ophthalmology exams with school aged children. Astigmatic vision disorders can significantly contribute not only to learning challenges, but also exclude a child from a peer group and cause socialization problems. If astigmatism is accompanied by nearsightedness- or farsightedness- and this often happens in adolescence- the child may be frightened by the severity and pace of changes associated with the development of the vision defects. Appropriate ophthalmological care and the selection of adequate glasses or contact lenses eliminates the problem and allows the child to reach his maximum potential.
Do symptoms of astigmatism change with age?
The prevalence of astigmatism of the power of minimum 1Dcyl cylinder diopter varies from 30% with children ages 0-4, to 50% during the first year of life, growing to a maximum up to 60% in the range of 1.5 – 2.5 years and lessens to 20-40% for children of the age of 5. Likewise, the degree lessens at an average of about 2.25 Dcyl cylinder diopters for children from 0-4 weeks to about 1 Dcyl cylinder diopters for 5-year olds. It is hard to catch astigmatism in preschoolers, because in the years of four to seven, it tends to lessen. But in school aged children, it can begin to be seen because of troublesome symptoms, which often parents do not relate with vision problems.
For people between the ages of 20 and 40, astigmatism evolves in such a way, that it is difficult to predict the way to change the defect. But after 40 years of age, there is some dependence: dependent upon the degree of the lessening of the value of the astigmatism in the eyes and differentiation between simple astigmatism and its growth in the eyes from reverse astigmatism.
Simple astigmatism – when the refraction of light in the vertical plane is stronger than in the horizontal plane; this tends to occur at birth, may be due to the “collapse” of the cornea in the still developing eyeball.
Inverse astigmatism – when refraction conditions are inverted, i.e. stronger refraction applies to the horizontal plane; it appears due to a pronounced stiffening of the upper eyelid, which presses on the horizontal meridian of the cornea, especially in an eye characterized by its low rigidity.
After the age of 60, astigmatism and cataracts often occur simultaneously. This results in a dangerous combination that greatly reduces the quality of life of older people and their safety (i.e. hinders changing lanes, judging the distance of oncoming vehicles and going down stairs.) The solution is the implantation of artificial toric intraocular lenses. They are implanted during cataract surgery, solving both problems- cataracts and astigmatism- simultaneously.
How can astigmatism be diagnosed?
Several tools are used to diagnose astigmatism. Keratoscope (Placido disk), namely a disk with black or white circles, which allows the observation of the shape of the circle reflections upon the cornea, the corneal topography and tomography. (Scheimpflug or OCT technology). The use of the manual Keratoscope is more and more infrequent because ophthalmologists and optometrists have at their disposal video cartography computers (digital)- for the exam they use the Placido disk image cast upon the surface of the cornea, which is then saved by the camera, sent to the computer where it can be analyzed. The effect of the exam is a map of the cornea, cross section of the surface and a digital map of the values of the curvature of the cornea. Specialists continually make use of the keratometer Javala, or manual keratometer, which serves to measure the curvature of the cornea in two main sections. Thanks to these measurements, they may precisely determine the degree and the axis of astigmatism. The manual keratometer is the gold standard in assessing the power and axis of astigmatism in calculating the toric lenses.
Astigmatism and its variety
Ophthalmologists and optometrists apply different designations to astigmatism.
Classification based upon focal length positioning, parallel to main sections, in relation to the retina by relaxed accommodations:
- Nearsighted astigmatism – one focal line lies on the retina, and the second in front of the retina,
- Farsighted astigmatism – one focal line lies on the retina, and the second beyond the retina,
- Complex shortsighted astigmatism – both focal lines lie in front of the retina,
- Complex farsighted astigmatism – both focal lines lie beyond the retina,
- Mixed astigmatism – one focal line is found in front of the retina, and the second beyond the retina, namely when the eye is farsighted in one area and is nearsighted in the second.
The classification is dependent upon the structure of the optical eye system, which is the source of astigmatism:
- corneal astigmatism – about 98% of diagnosed cases are based on an improper shape of the cornea, which instead of resembling the shape of a ball fragment is more similar to the surface of a rugby ball,
- lenticular astigmatism – associated with an improper shape of the eye lens,
- mixed astigmatism – defective structure of the eye lens co-occurring with a corneal deformity.
The classification associated with “steepness” responsible for the refractive power of the cornea in the eye with astigmatism:
- regular astigmatism – the size of the defect is equal to the difference in refractive power between two main sections, with the largest and smallest refraction that form a right angle together,
- simple regular astigmatism – the cornea is steeper in the vertical section than in the horizontal,
- regular inverse astigmatism (opposite to the rule): the refraction of light is greater in the horizontal plane,
- oblique regular astigmatism: the meridian with the highest breaking power is located in the ranges from 31 degrees to 59 degrees or from 121 degrees to 149 degrees,
- irregular astigmatism – there are no main sections crossing at right angles or there are more than two.
In specialized literature, we encounter a greater number of divisions and designations for individual types of astigmatism. As you can see, this is a complex defect that requires a precise diagnosis. The more complicated the defect, the greater the likelihood that laser astigmatism correction will be needed.
Methods for astigmatism treatments
In the past, astigmatism treatment was only possible by traditional vision correction methods, namely by suggesting that patients find the proper eye glasses. However, today technological advance has opened before us new solutions and techniques, which are connected to far better and faster effects and increased comfort for the patient.
As has already been stated, in the uncomplicated condition of astigmatism, only corrective lenses are required or utilizing toric contact lenses. In more complicated cases (i.e. irregular astigmatism), although thanks to the current state of knowledge they are easily diagnosed, they with difficulty respond or fail to respond to corrective glasses.
Eye glasses are often insufficient even for wearers with regular astigmatism. Despite the right choice of cylindrical glass lenses (having different shatter proof degrees in the main perpendicular meridians/planes, i.e. they focus the light in two different points), the patient may still experience a sight disorder. These symptoms make it difficult to, i.e. drive a car. In such cases, the ophthalmologist directs the wearing of only toric contact lenses. They assist in the correction of virtually 99% of the cases of astigmatism. The optical zone of such lenses has differing breaking power in the main perpendicular planes and focuses the light in two different points, thus correcting in this way the vision defect caused by astigmatism.
If neither glasses nor contact lenses bring the desired result, then you need to resort to traditional surgical methods, such as the aforementioned implantation of intraocular one-, two- or three- focal toric lenses- or laser surgery.
In our clinic, the laser vision correction procedure is performed by a qualified team of doctors, who display professional skills in the latest treatment methods. The laser correction of astigmatism is one of the safest treatment methods and instantly improves the patient’s quality of life.
Laser astigmatism correction
The advantage of the most modern laser in relation to the treatment of astigmatism in the SwissLaser clinic is the very exact correction that is possible thanks to the use of the so-called “static cyclorotation compensation.”
An astigmatism operation is performed using the following methods:
- Femto-LASIK (All-Laser-LASIK): thanks to the precision femtosecond laser, the surgeon makes a small incision on the cornea, creating a thin flap about .1mm in width. Using an excimer laser, he can fashion the previously uncovered cornea in a few seconds and then return the flap; it reattaches and creates a protective barrier for the cornea.
- LASIK (laser assisted in situ keratomileusis): a two-stage technique; the cornea is incised with the help of a mechanized scalpel (microkeratome), and then the surface of the cornea is fashioned so that it may effectively focus the image on the retina.
- LASEK/PRK/TRANS-PRK SMART SURFACE: the treatment relies on the deviation (LASEK) or mechanical removal (PRK), laser removal (TRANS-PRK) of the upper layer of the corneal epithelium, followed by the appropriate fashioning of the underlying corneal tissue with an excimer laser. The purpose of this procedure is to properly fashion the central corneal surface with a laser beam so that it focuses the image properly on the retinal surface.
Why is it worth it?
Astigmatism is an ailment, which undoubtedly hinders daily living. Connected to the lack of the ability to focus clearly, which causes constant drainage of the eye, it can also cause headaches.
This defect can reduce the quality of life due to the fact that images that the patient sees are ill formed, which exposes him and his surroundings to danger, for example on the road. Related also is the difficulty with vision both far and near, and combining a cataract in advanced years, can result in poor self-confidence.