Astigmatism
Warsaw · Krakow · Vienna · Zurich
If we consult an ophthalmologist due to blurred vision of details both at a distance and up close, we most often hear the diagnosis: astigmatism. Astigmatism is not an eye disease, but a refractive error, meaning that the eye’s optical system is unable to properly focus light rays on the retina.
Astigmatism – what is it?
Parallel light rays refract in two different planes (e.g., vertical and horizontal), resulting in blurred vision, image distortion and wavering, and poor contrast. Colloquially speaking, an astigmatic person constantly feels as if they are intoxicated: straight lines waver, they cannot achieve sharp focus despite their best efforts, and they experience disturbances in spatial perception. This blurred vision significantly hinders daily activities.
It is estimated that approximately 40% of the population has a defectively structured cornea or lens, and consequently, symptoms of astigmatism. It cannot be avoided – the defect is hereditary, and our lifestyle has no impact on its development. Nearly 50% of patients diagnosed with astigmatism experience such a significant impairment in vision quality and associated comfort in daily functioning that they require ophthalmological assistance.
In uncomplicated cases, glasses with cylindrical lenses or toric contact lenses are sufficient. In more complex cases, it is worth considering laser astigmatism correction, for example, using the FemtoLASIK method, or undergoing lens replacement surgery.
Symptoms that may suggest the presence of astigmatism
If we consult an ophthalmologist due to blurred vision of details both at a distance and up close, we most often hear the diagnosis: astigmatism. Astigmatism is not an eye disease, but a refractive error, meaning that the eye’s optical system is unable to properly focus light rays on the retina.
Parallel light rays refract in two different planes (e.g., vertical and horizontal), resulting in blurred vision, image distortion and wavering, and poor contrast.
Colloquially speaking, an astigmatic person constantly feels as if they are intoxicated: straight lines waver, they cannot achieve sharp focus despite their best efforts, and they experience disturbances in spatial perception. This blurred vision significantly hinders daily activities.
It is estimated that approximately 40% of the population has a defectively structured cornea or lens, and consequently, symptoms of astigmatism. It cannot be avoided – the defect is hereditary, and our lifestyle has no impact on its development.
Nearly 50% of patients diagnosed with astigmatism experience such a significant impairment in vision quality and associated comfort in daily functioning that they require ophthalmological assistance.
In uncomplicated cases, glasses with cylindrical lenses or toric contact lenses are sufficient. In more complex cases, it is worth considering laser astigmatism correction, for example, using the FemtoLASIK method, phakic lens implantation, or undergoing lens replacement surgery.
Symptoms that may suggest the presence of astigmatism
In addition to blurred vision both at a distance and up close, astigmatism can also manifest with other ailments related to the patient constantly squinting and rubbing their eyes to improve vision quality. These include:
- headaches,
- a sensation of dizziness,
- a sensation of amblyopia (lazy eye),
- rapid fatigue during activities requiring visual focus, e.g., while working at a computer or driving.
While an adult will immediately seek ophthalmological help, in the case of a child, it may take a long time before we realize that headaches, reluctance to read, or problems with motor coordination are not neurological or psychological in origin, but are related to vision problems. Therefore, it is crucial to conduct preventive ophthalmological examinations in school-aged children.
Astigmatic vision disorders can significantly contribute not only to academic failures but also exclude a child from their peer group and become a cause of socialization problems. If astigmatism is accompanied by myopia or hyperopia – which often happens during adolescence – the child may be terrified by the intensity and pace of changes related to the development of refractive errors.
Appropriate ophthalmological care and the selection of adequate glasses or contact lenses eliminate the problem and allow the child to maximize their potential.
Do astigmatism symptoms change with age?
The prevalence of astigmatism with a minimum power of 1.00 diopter cylinder ranges from 30% in children aged 0–4 weeks to 50% within the first year of life, increasing to a maximum of 60% between 1.5–2.5 years, and decreasing to 20–40% in children aged 5 years. Its power also decreases on average by approximately 2.25 diopters cylinder in children aged 0–4 weeks to about 1.00 diopter cylinder by the age of 5.
It is difficult to detect astigmatism in preschoolers because it tends to decrease between the ages of four and seven, but by school age, it can start to cause the alarming symptoms described above, which parents do not associate with vision problems at all.
In individuals aged 20-40, astigmatism evolves in a way that makes it difficult to predict the direction of refractive error changes. However, after the age of 40, a certain correlation becomes apparent: it involves a gradual decrease in astigmatism values in eyes with simple astigmatism and an increase in eyes with inverse astigmatism.
Astigmatism and Cataracts – Modern Treatment Methods
The solution is the implantation of toric intraocular lenses. These are implanted during cataract removal surgery, addressing both problems – cataracts and astigmatism – simultaneously.
Simple astigmatism (with-the-rule astigmatism) – when light refraction in the vertical plane is stronger than in the horizontal plane; it tends to occur at birth and may result from the “collapse” of the cornea in a still-developing eyeball.
Inverse astigmatism (against-the-rule astigmatism) – when the light refraction conditions are reversed, meaning stronger light refraction occurs in the horizontal plane; it appears due to significant stiffening of the upper eyelid’s tarsal plate, which presses on the horizontal meridian of the cornea, especially in an eye characterized by low corneal rigidity.
After the age of 60, astigmatism and cataracts often occur simultaneously. This results in a dangerous combination that significantly reduces the quality of life for older individuals and their safety (e.g., making it difficult to cross the street, estimate the distance to an approaching vehicle, or descend stairs).
How is astigmatism diagnosed?
Several tools are used to diagnose astigmatism.
A keratoscope (Placido’s disc), which is a disc with black and white circles, allows observation of the shape of the circle reflections on the cornea. Manual keratoscopes are increasingly less common, as ophthalmologists and optometrists have access to computer videokeratographs (digital) – the examination uses an image of Placido’s disc projected onto the corneal surface, which is then recorded by a camera, sent to a computer, and analyzed.
The result of the examination includes a corneal map, a cross-section of the corneal surface, and a map of digital corneal curvature values. Specialists also still use Javal’s ophthalmometer (keratometer), a manual keratometer used to measure corneal curvatures in two main meridians.
These measurements allow for precise determination of the magnitude and axes of astigmatism. Manual keratometry is the gold standard in assessing the power and axis of astigmatism for toric lens calculation.
Astigmatism and its varieties
Ophthalmologists and optometrists use various classifications of astigmatism.
Classification by the position of focal lines relative to the retina
| Type of Astigmatism | Characteristics |
| Myopic | One focal line lies on the retina, the other in front of the retina |
| Hyperopic | One focal line lies on the retina, the other behind the retina |
| Compound Myopic | Both focal lines are located in front of the retina |
| Compound Hyperopic | Both focal lines are located behind the retina |
| Mixed | One focal line in front of the retina, the other behind the retina |
Classification by the source of the defect in the eye’s optical system
| Type of Astigmatism | Characteristics |
| Corneal | Most common (approx. 98% of cases); results from an irregular corneal shape |
| Lenticular | Caused by an irregular lens shape |
| Mixed (corneal-lenticular) | Coexisting corneal and lenticular abnormalities |
Classification by corneal “steepness” (regularity)
| Type of Astigmatism | Characteristics |
| Regular | Difference in refractive power between two main meridians perpendicular to each other |
| – Simple Regular | Cornea steeper in the vertical meridian |
| – Inverse Regular | Greater refractive power in the horizontal plane |
| – Oblique Regular | Greatest refractive power in the range of 31°–59° or 121°–149° |
| Irregular | Absence of two main perpendicular meridians or more than two present |
Astigmatism – a defect requiring precise diagnosis
In specialized literature, we encounter a greater number of classifications and names for individual varieties of astigmatism. As can be seen, it is a complex defect requiring precise diagnostics. The more complicated the defect, the higher the probability that laser astigmatism correction will be necessary.
Methods of astigmatism treatment
As mentioned, in uncomplicated cases, astigmatism only requires spectacle correction or the use of toric contact lenses.
More complicated cases (e.g., irregular astigmatism), although easily diagnosed thanks to the current state of knowledge, are difficult or impossible to correct with spectacle lenses.
Glasses are sometimes insufficient even for a user with regular astigmatism. Despite correctly chosen cylindrical lenses (which have different refractive powers in the main perpendicular meridians/planes, meaning they focus light at two different points), the patient may still experience disturbances in spatial vision and have difficulty assessing distances and object dimensions.
These symptoms make it difficult, for example, to drive a car. In such cases, the ophthalmologist prescribes wearing only toric contact lenses. They can correct virtually 99% of astigmatism cases. The optical zone of such lenses has different refractive powers in the main perpendicular planes and focuses light at two different points, thereby correcting the refractive error caused by astigmatism.
If neither spectacle lenses nor contact lenses yield the desired result, traditional surgical methods, such as the aforementioned implantation of single-, bi-, or trifocal toric intraocular lenses, or laser surgery, must be considered.
astigmatism
Laser correction for astigmatism
The advantage of the most modern laser used in astigmatism treatment at the SwissLaser clinic is highly accurate correction possible thanks to the application of static cyclorotation compensation.
Astigmatism surgery is performed using the following methods:
Femto-LASIK (All-Laser-LASIK)
Using a precise femtosecond laser, the surgeon makes an incision in the cornea, creating a thin flap 0.1 mm thick. An excimer laser is then used to reshape the exposed cornea for a few seconds, after which the flap is repositioned; it adheres and forms a protective barrier for the cornea.
LASIK
Two-stage technique: the cornea is incised with a scalpel (microkeratome), and then the corneal surface is reshaped so that it can properly focus the image onto the retina.
LASEK/PRK
The procedure involves lifting (LASEK) or removing (PRK) the upper cellular layer of the cornea (epithelium), and then appropriately reshaping the underlying corneal tissue using an excimer laser. The goal of the procedure is to precisely reshape the central corneal surface with the laser beam so that it focuses the image accurately onto the retina.
