Corneal curvature Cause: Dr. med. Bányai clarifies
The most common cause of corneal curvature (astigmatism) is genetic predisposition: the cornea does not grow evenly round, but slightly oval. As a result, the light hits the retina at two different points and the image remains blurred. In most cases, the defective vision is congenital and inherited from the parents.
In addition to genetics, corneal diseases (such as keratoconus), injuries, and certain eye surgeries can also cause or exacerbate astigmatism. In this article, we will explain exactly how this occurs and which factors can worsen an existing corneal curvature.
A distinction is made between regular astigmatism (correctable with glasses, contact lenses or permanently with a refractive eye laser treatment) and irregular astigmatism (best possible correction usually with dimensionally stable contact lenses, in selected cases also with topography-guided laser procedures).
How does a corneal curvature occur?
A corneal curvature (astigmatism) is caused by different refractive powers of the eye or an uneven curvature of the cornea. The cornea is a clear, convex layer that covers the front of the eye and directs the incident light to the lens. When the cornea is unevenly curved, the incident light rays are not properly refracted and focused on the retina, resulting in blurred vision.
People with astigmatism can see blurred, both near and far. You have difficulty recognizing contrasts and details, and objects may appear distorted or blurry. Astigmatism often occurs in combination with other refractive errors such as nearsightedness (myopia) or farsightedness (hyperopia).
Cause of corneal curvature: Overview of the most important factors
There are several factors that can lead to uneven curvature of the cornea:
- Genetic predisposition: Astigmatism is often hereditary and is passed on from parents to children.
- Injuries: An injury to the eye that changes the shape of the cornea can also lead to astigmatism.
- Corneal diseases: Certain corneal diseases, such as keratoconus, a condition in which the cornea gradually becomes thinner and more conical, can also cause astigmatism.
- Eye surgery: Eye surgery, especially those involving the cornea, can lead to astigmatism if the shape of the cornea is not restored correctly.
- In some cases, refractive errors such as myopia or hyperopia can also promote astigmatism.
Most people with astigmatism have a genetic predisposition, and most cases are congenital. A recent meta-analysis confirms this assessment: according to it, up to 46% of the differences in refractive astigmatism are due to genetic factors.¹ However, it is also possible that a corneal curvature develops or intensifies in the course of life, for example due to injuries, eye surgery or a corneal disease such as keratoconus.
How common is a corneal curvature?
Corneal curvature is widespread. In Germany, the Gutenberg Health Study with over 13,500 adults shows that around 13% have a clinically relevant astigmatism of more than one diopter.² Worldwide, the prevalence is between 8 and 62%, depending on the study and definition.³
A recent meta-analysis also shows that genetic factors are responsible for around 46% of the variability in refractive astigmatism. The corneal curvature itself is even 64% hereditary.¹ This explains why astigmatism is so common in families.
Does a corneal curvature get worse?
Corneal curvature usually does not worsen on its own. However, vision problems can worsen over time if left untreated. Without proper correction, astigmatism can become a constant vision problem that leads to headaches, eye strain, and fatigue.
However, in some cases, a corneal curvature can progress, especially if it is caused by an illness or injury. Keratoconus, for example, a corneal disease in which the cornea gradually becomes thinner and more conical, leads to progressive, irregular astigmatism.⁴
It is therefore important to have regular ophthalmological examinations. While glasses and contact lenses only compensate for defective vision, refractive laser eye treatment permanently corrects the cornea, so that many patients can then live without glasses. This can improve visual acuity, reduce eye strain and reduce the risk of headaches.
Astigmatism test
Think you have a corneal curvature? With the online astigmatism test, you can make an initial assessment. Only an ophthalmologist can make a concrete diagnosis.
Corneal curvature lasers
Glasses, contact lenses and toric intraocular lenses can compensate for a corneal curvature, but do not remedy it. If you want to live permanently without glasses, refractive laser eye treatment is the most effective solution for you.
With modern procedures such as SMILE® Pro, Femto-LASIK or PRK, the cornea is precisely reshaped, so that in many cases you can do without vision aids after the procedure. Which procedure is right for you depends on the degree of refractive error, corneal thickness and general eye health.
Treating corneal curvature – with Bányai Neue Augen in Stuttgart and Karlsruhe
Dr. med. Daniel Bányai and the team of Bányai Neue Augen have been accompanying patients with corneal curvature for over 28 years. With more than 51,000 successful treatments and over 3,000 procedures per year, our laser eye centers in Stuttgart and Karlsruhe have the experience needed for precise and individual therapy.
Whether your corneal curvature is congenital or acquired: With modern procedures such as SMILE® Pro, Femto-LASIK or PRK, we enable many patients to live without glasses and contact lenses. Many of our patients report that they were able to see clearly for the first time after treatment without reaching for their glasses in the morning. We will clarify together which path is the right one for you personally in a non-binding consultation.
Frequently Asked Questions About Corneal Curvature Cause
We have summarized the most common questions that patients ask us about the causes of corneal curvature here.
The most common cause is genetic predisposition. If parents have a corneal curvature, there is an increased chance that their children will also be affected. Studies show that genetic factors explain up to 46% of the differences in astigmatism. In most cases, refractive error is congenital.
Yes, astigmatism is largely hereditary. Scientific research shows that parents with corneal curvature significantly increase the risk for their children. The exact genes that play a role in this are still the subject of research. The defective vision is therefore usually unavoidable, but can be easily corrected.
Congenital corneal curvature often remains stable for years. However, it can worsen if there is an underlying condition such as keratoconus. Keratoconus is a corneal disease in which the cornea becomes progressively thinner and conical. This form of astigmatism can be progressive and requires specific treatment, such as corneal cross-linking.
The most well-known corneal-related cause is keratoconus, a condition in which the cornea becomes progressively thinner and takes on an irregular, conical shape. Keratoconus leads to irregular astigmatism, which can often no longer be completely corrected with glasses. Other triggers can be injuries to the cornea or certain eye operations.
Yes, it is possible. Even without astigmatism in the family, a corneal curvature can occur, for example due to an injury to the eye, corneal surgery or as a result of a disease such as keratoconus. However, such acquired forms are significantly less common than congenital cases.
The permanent and tool-free solution is the refractive laser eye treatment. Modern procedures such as SMILE® Pro, Femto-LASIK or PRK reshape the cornea in such a way that light beams are focused precisely on the retina again. Many patients then live without glasses and contact lenses. Glasses, contact lenses or toric intraocular lenses are other options, but they only compensate for the defective vision instead of correcting it.
References
¹ Shing E, Kam KW, Zaabaar E, et al. (2025): Heritability and Genetic Factors of Astigmatism and Corneal Curvature: A Systematic Review and Meta-analysis. American Journal of Ophthalmology.
² Schuster AK, Pfeiffer N, Nickels S, et al. (2017): Refractive, corneal and ocular residual astigmatism: distribution in a German population and age-dependency – the Gutenberg Health Study. Graefes Arch Clin Exp Ophthalmol.
³ Zhang J, Wu Y, Sharma B, et al. (2023): Epidemiology and Burden of Astigmatism: A Systematic Literature Review. Optometry and Vision Science.
⁴ Santodomingo-Rubido J, Carracedo G, Suzaki A, et al. (2022): Keratoconus: An updated review. Contact Lens and Anterior Eye.
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