A blur unlike any other. Not just at distance or up close: at every distance. For the vast majority of profiles, it is very effectively corrected.
Thomas is 35. He sees blurry but not like his myopic friends. At distance and up close, contours are doubled. Letters overlap slightly. At night, headlights burst into stars.
Astigmatism is often misunderstood, sometimes confused with myopia. Yet it is a refractive error in its own right with its own mechanisms, its own symptoms, and its own solutions.
Imagine a rugby ball placed on the cornea, instead of a round ball. 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.
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.[1]
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.[2]
With associated myopia or hyperopia. Astigmatism frequently accompanies another refractive defect. Surgical correction treats them simultaneously.
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.[3]
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. A 10-degree error on this axis reduces correction efficacy by 30%. The precision of the exam is decisive.
References
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 does not follow this symmetrical pattern. 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.
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.
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.