Astigmatism surgery in Paris
Patients with astigmatism experience blurred vision both at near and far distances. This condition is most often caused by a deformed cornea with an irregular curvature. There are several surgical techniques to correct astigmatism: laser, implant, or lens surgery.
Learn more about other vision issues
Myopia
Presbyopia
Hyperopia
General information on astigmatism
The cornea and the lens are two natural lenses that refract light rays entering the eye. By altering their direction, these rays normally converge at a single point, allowing the image to form on the surface of the retina. This precise focusing is possible because the cornea typically has a constant and regular curvature.
However, in patients with astigmatism, the cornea is irregular. It becomes more oval-shaped, causing light rays to focus at two different points instead of one. As a result, the person sees blurred images at all distances, and in some cases, vision may also be distorted along a particular axis.
Astigmatism frequently causes headaches and mild visual fatigue. To varying degrees, it affects nearly 85% of the population, but when mild, it does not always require correction.
Astigmatism is rarely an isolated defect (simple astigmatism). It is most often associated with another refractive error (ametropia): myopia or hyperopia. This is then called compound astigmatism.
In addition to wearing glasses or contact lenses, surgery now offers several ways to treat astigmatism. These are relatively common procedures, most often performed with a laser (Lasik and PRK techniques). They can simultaneously correct associated myopia or hyperopia. Astigmatism can also be corrected with a phakic lens implant in cases of severe ametropia, or, depending on the patient’s age and preoperative clinical assessment, by lens surgery.
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Laser surgery for astigmatism
Whether using the PRK or Lasik method, laser surgery for astigmatism involves photoablation (Excimer laser) of a superficial layer of the cornea. The goal is to restore a regular curvature so that refracted light rays then converge at a single, sharp focal point. More specifically, the laser is applied to the corneal stroma, the intermediate layer of the cornea located beneath the epithelium and above the endothelium.
The choice between these two techniques depends on the results of the preoperative assessment. In particular, corneal thickness is crucial. If it is less than 500 micrometers, PRK, which works more superficially on the stroma, is preferable. Similarly, some activities lead to avoiding Lasik, especially those with a high risk of eye trauma, such as combat sports or certain professions (firefighters, police officers, etc.).
Both methods differ mainly in how they access the corneal stroma for laser treatment. These are quick outpatient procedures (maximum 30 minutes), performed under local anesthesia (anesthetic eye drops).
Lasik for astigmatism surgery
The LASIK method is characterized by its first step: cutting a thin flap of the cornea, the “stromal flap,” with a femtosecond laser. This flap is then lifted to access the corneal layers to be treated. Once the stroma is reshaped, the flap is repositioned. Although the corneal surface is temporarily weakened, it remains intact at the end of the procedure.
Recovery after Lasik is rapid. In most cases, vision, which may be slightly blurred immediately after the procedure, becomes clear again within a few hours.
PRK laser surgery for astigmatism
Access to the stroma is different in PRK surgery. The surgeon gently peels away part of the corneal epithelium. As with Lasik, the stroma is then treated with the Excimer laser, but more superficially. Because of the initial step, the corneal epithelium must regenerate and heal during the postoperative period.
This healing takes a few days and may cause discomfort or pain for about 48 hours. Vision generally becomes clear progressively within a week after the procedure.
Astigmatism correction with phakic lenses
When astigmatism is associated with ametropia too severe for laser surgery, placing an implant under the iris and in front of the lens is a first-rate solution. The quality of the implant material is crucial to avoid any risk of rejection.
ICL implants from STAAR are among the best available today. Made from collamer, an extremely biocompatible material, they are very well tolerated. The medical community has extensive experience with these implants, which have been used since the 1990s. Over 200,000 such procedures are performed worldwide each year.
Phakic lens implants can correct astigmatism from 0.5 to 6 diopters, associated with hyperopia from +0.5 to +10 diopters. Mild to severe myopia can also be treated, from -0.5 to -18 diopters.
During the procedure, the artificial lens is inserted into the eye, between the iris and the lens, rolled up through a small incision. It then unfolds and positions itself in place.
This is a completely reversible technique that also avoids the dry eye syndrome sometimes seen after laser refractive surgery.
Toric hypermetropic ICL
Toric myopic ICL
Astigmatism treatment by lens surgery
Lens surgery for astigmatism is especially for patients over 60. It is similar to cataract surgery: the lens is removed and replaced with an artificial intraocular lens. The optical properties of the implant are determined based on preoperative assessments, so the lens power can correct astigmatism and any associated ametropia.
Intraocular lenses that correct astigmatism are called “toric implants.” They are custom-made, with greater power in one axis to specifically correct astigmatism, as well as any associated myopia or hyperopia. Preoperative calculations are used to precisely define the axis for implant placement during surgery.
Frequently asked questions
Is LASIK for astigmatism more complex than for other vision disorders like myopia or hyperopia?
Yes, correcting astigmatism with laser photoablation is more complex. For myopia, the procedure flattens the central corneal curvature, while for hyperopia, the peripheral cornea is reshaped to increase its curvature. Myopia and hyperopia are not “oriented” visual defects, whereas astigmatism is due to different curvatures along the corneal meridians. Therefore, both the degree and the axis of astigmatism must be determined preoperatively, and the orientation of the Excimer laser during surgery is crucial to provide the necessary correction along the correct axis.
This is why the stromal flap is always cut with a femtosecond laser during Lasik for astigmatism treatment, as this increases the precision of the flap in terms of size, shape, and location.
Can glasses be used instead of surgery to correct astigmatism?
Yes, astigmatism can be corrected with glasses or contact lenses. This is a common solution, especially since it is partially reimbursed by health insurance. However, over several years, refractive surgery (laser or implant) may be more cost-effective, despite the higher initial cost.
Corrective lenses for astigmatism are called “toric” lenses: they provide different degrees of correction along different axes. They are more complex to make than lenses for myopia or hyperopia and must be properly aligned to be effective. Astigmatic patients should avoid round lenses, which may rotate. Contact lenses are weighted at the bottom to maintain correct alignment.
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This page was written by Dr. Camille Rambaud, an ophthalmologist based in Paris and a specialist in refractive surgery.
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