Astigmatism is the most common ametropia and it is most often moderate. Ophthalmologists cannot yet determine the causes of astigmatism except in cases of pathology of the cornea (keratoconus).
A preoperative assessment is essential in refractive surgery.
It allows your surgeon to choose the most appropriate surgical technique for you (which may be PRK, LASIK, or implants) and to check the absence of contraindications.
Indeed, even if refractive surgery corrects visual defects (myopia, hyperopia and astigmatism), compliance with the contraindications avoids post-operative complications. The quality of the preoperative indication determines the quality of the result. This consultation also helps to answer the patient’s questions.
At Clinique de la Vision, for example, a preoperative consultation includes:
- Measurement of ametropia (visual defect) to be corrected by refraction analysis
- The complete ophthalmic assessment with measurement of the intraocular pressure, examination of the fundus and especially the analysis of the transparency of the lens
- The analysis of corneal morphology (curvature, shape, thickness) thanks to corneal topography eliminates the contraindications to laser surgery and to choose the most appropriate surgical technique for the patient
- Aberrometric examination analysis of the optical quality of the eye
- We calculate the implant if we’re considering lens surgery
- Other explorations can be done depending on the context.
It is only at the end of this assessment that a surgeon can make a recommendation, and choose the most suitable refractive surgery technique for you. The surgeon will clearly explain the advantages, the possible undesirable effects and the expected results of their recommended procedure.
Like other ametropia, surgeons can correct astigmatism with several laser techniques (PRK, LASIK, SMILE).
The principle is then to regularise the curvature of the corneal meridians to erase the difference between the flatter meridian and the more domed meridian. Doing so makes the eye emmetropic by converging light beams no longer in two focal lines but at one point.
The goal is to equalise the radius of curvature between the two extreme meridians. When the astigmatism is associated with a strong ametropia, the correction can also be done by phakic implant type ICL .