Definition : non-spherical cornea (rugby ball shape). Two curvatures depending on the axis → doubled image at all distances.
Symptoms : doubled outlines, halos and stars around light sources at night, visual fatigue.
Surgical solutions : Femto-LASIK up to 5 D, PRK for mild astigmatism, toric ICL beyond.
Technical criterion : topography precisely measures the axis → key parameter for correction.
Distinction : regular astigmatism (operable) vs irregular / keratoconus (not operable with laser).
Indicative price : 1700-2250 € per eye for laser, 2700-3500 € per eye for toric ICL.
Understanding
What is astigmatism exactly?
The astigmatic cornea resembles a rugby ball placed on the eye, rather than a round one. The normal cornea is spherical: it bends light identically in all directions. The astigmatic cornea, however, has two different curvatures depending on the axis: more curved in one direction, flatter in the other.
The result: light entering the eye does not converge to a single sharp point on the retina. It forms two offset foci. The image is blurry, distorted, doubled in certain directions. Not just at distance or up close: at every distance.
A regular cornea. Its curvature is the same in every axis, like the surface of a football. The rays converge on a single point on the retina.
An astigmatic cornea. It is steeper in one axis than in the other, like a rugby ball. The rays converge into two lines instead of a point, and the image is distorted at every distance.
This is the fundamental difference with myopia: the myope sees blurry at distance, sharp up close. The astigmate sees imprecisely everywhere, often with an "almost sharp" sensation that tires the eye more than a clear blur.
What it changes in daily life
Contours that double. Letters on a sign, numbers on a screen, faces at a distance: everything seems slightly overlapped. Many astigmatic patients read more slowly without understanding why.
Permanent visual fatigue. The eye constantly tries to correct an image that cannot be sharp. This unconscious work generates chronic ocular fatigue: heavy eyes, burning sensation, headaches at the end of the day. Often blamed on screens, they disappear after correction.
At night, the most bothersome symptom. Halos, stars around light sources, headlights that "burst" in the visual field. Night driving is often the moment when patients truly realise the extent of their condition.[1]
With associated myopia or hyperopia. Astigmatism frequently accompanies another refractive defect. Surgical correction treats them simultaneously.
The degrees of astigmatism
Low astigmatism · up to 1 D Often uncorrected or poorly detected. Symptoms mainly of fatigue and slight visual imprecision.
Moderate astigmatism · 1 to 3 D Daily discomfort. Difficulties with prolonged reading, night halos. Surgery gives excellent results in this range.
High astigmatism · beyond 3 D Blurry and distorted vision at every distance. For profiles not eligible for laser, toric ICL implants represent an effective alternative.
Astigmatism has an axis along which the cornea is most deformed. That is why two patients with the same degree can have very different symptoms. The exam precisely measures this axis: it is fundamental for calculating the laser treatment or choosing the appropriate toric implant.[2]
Surgical options
Femto-LASIK and PRK Correct astigmatism by reshaping the cornea along its precise axis. Excellent results for low to moderate astigmatism.
Toric ICL Implant specially designed for high astigmatism associated with significant myopia. Without corneal ablation.
The axis, a key parameterCorneal topography precisely measures the astigmatism axis. An error of a few degrees on this axis noticeably reduces the efficacy of the correction. The precision of the exam is decisive.
References
Black AA, Wood JM, Colorado LH, Collins MJ. The impact of uncorrected astigmatism on night driving performance. Ophthalmic Physiol Opt. 2019;39(5):350-357. doi:10.1111/opo.12634.
Alpins N. Astigmatism analysis by the Alpins method. J Cataract Refract Surg. 2001;27(1):31-49.
Frequently asked
What patients often ask
Can astigmatism be corrected by laser surgery?
Yes. Femto-LASIK and PRK correct astigmatism by reshaping the cornea along its precise axis. For high astigmatism associated with high myopia, toric ICL implants offer an alternative without corneal ablation.
Can you have myopia and astigmatism at the same time?
Yes, it is even very common. The two defects often add up. Surgery corrects them simultaneously in a single procedure.
Can astigmatism prevent laser surgery?
High astigmatism with a cornea that is too thin can contraindicate laser. In that case, toric ICL implants represent an effective alternative.
Regular and irregular astigmatism: a difference that changes everything
Regular astigmatism, by far the most common, presents two main meridians perpendicular to each other. It is the one that glasses, contact lenses and laser surgery effectively correct. Irregular astigmatism shows disordered meridians. Keratoconus is the most common example: a progressive deformation of the cornea that takes a cone shape.
Keratoconus is a formal contraindication to any laser surgery. That is why corneal topography (a three-dimensional map of the corneal surface) is an essential exam in the preoperative workup. It detects early forms of keratoconus before they are even symptomatic.
Correction by degree
Which solution for which degree of astigmatism?
Low astigmatism (below 1.5 dioptres) can often be corrected with spherical contact lenses. From 1.5 dioptres, cylindrical correction is necessary. Laser surgery (Femto-LASIK or PRK) effectively corrects astigmatism up to 5-6 dioptres. Beyond that, toric ICL implants offer a precise and reversible alternative.
Astigmatism can evolve with age, particularly in connection with the development of a cataract, which progressively alters the optical properties of the crystalline lens. A correction stable for two years is the standard criterion before considering refractive surgery.
CORRECTING YOUR ASTIGMATISM IN BRUSSELS
For the vast majority of profiles, astigmatism is effectively corrected by refractive surgery. The initial consultation allows the technique best suited to your degree of astigmatism and corneal condition (Femto-LASIK, PRK or toric ICL implant) to be determined. It is available within one to two weeks. Corneal topography, performed during the preoperative exam, is the key test that guides the choice of technique.
Author of this page
Dr Serdal Sanak
Ophthalmic surgeon · Refractive and cataract surgery
CHIREC Hôpital Delta, Brussels
Graduated from the ULB, trained at CHU de Liège and CHIREC. European Diploma in Ophthalmology (FEBO). Refractive and cataract surgery make up the bulk of my operating activity, with procedures every week at CHIREC Delta. Dual specialisation: corneal laser surgery (Femto-LASIK, PRK) and intraocular surgery (ICL, PRELEX, cataract). Consultations in French, Dutch, English, Turkish, Kurdish, Persian and Italian.
