ASTIGMATISM : A NOT VERY ROUND CORNEA
The astigmatic eye presents abnormalities of corneal curving. One can say that the eye is shaped like an oblong rugbyball instead of a spherical football.. This abnormality induces blurry far and near vision with double vision of the image as well as headaches.
When refractive surgery candidates know that myopia can be treated, they often ask whether astigmatism can be corrected.
The answer is yes. It is possible to correct astigmatism up to 6 Diopters and it is also possible to treat a combination of defects (myopia or hyperopia with astigmatism).
Surgeries for the correction of astigmatism
"SURFACE" TECHNIQUES PRK, LASEK AND EPILASIK
Surface techniques are very easy to perform surgical procedures and free of operation complications.
The surgeon proceeds with the cornea preparation by manual abrasion in case of PRK. For LASEK, the surgeon uses a diluted alcoholic solution to prepare the cornea. Finally, the most recent surface technique is EpiLASIK: here the surgeon uses an automated motor to prepare the cornea.
The correction is then performed with the excimer laser
These techniques can treat light myopic astigmatism (up to 2 diopters).
Besides this indication, the higher the correction, the more the patient will be exposed to a risk of abnormal healing (Haze phenomenon) and regression (loss of part of the correction). Their major disadvantage is the immediate post-operative discomfort and the slower recovery time.
Learn more about PRK - LASEK - EpiLASIK
IN DEPTH TECHNIQUES,
WITH CUTTING : LASIK AND FEMTOLASIK
Cutting techniques (LASIK and FemtoLASIK) require skills and experience from the surgeon. The operative complication rates are low (1%).
The surgical risk is related to the creation of the corneal cap or flap. This cap is performed by an automated microkeratome in case of LASIK or by a femtoseconde laser in case of FemtoLASIK.
The correction is then performed with the excimer laser.
These techniques can correct astigmatism up to 6 diopters.
Learn more about LASIK - FemtoLASIK
TECHNIQUES WITH DOUBLE CUTTING RELEX SMILE
This technique currently does not correct astigmatism.
THE PHAKIC IMPLANTS
It is not always possible to correct myopia with laser treatment: the impairment can be too important or the cornea too thin.
The placement of a phakic intraocular lens can correct astigmatism. The two best-known phakic lenses are the ICL implant from Staar and the Artisan implant from Ophtec.
This solution is usually only offered when the astigmatism is associated with strong myopia and the patient is not treatable by laser.
Learn more about phakic intraocular lenses
When the patient experiences a decrease in visual acuity due to a cataract, lens surgery removes the cataract and places a lens that will correct the defect at the same time.
Lenses correcting astigmatism are toric lenses. They need to be placed in the eye in a very accurate axis, which is why the surgeon must be equipped with a lens positioning aid system such as the Verion Vision System.
"Clear lens surgery" or removal of crystalline that does not have cataract yet is not recommended for patients under 45 years of age because it deprives them of any accommodation (ability to focus on the near vision).
Learn more about lens surgery and cataract surgery