Whereas a normal cornea is circular, it becomes oval-shaped in cases of astigmatism. This condition distorts vision at any distance, and can be combined with myopia or hyperopia.
Several surgical procedures are available. If you are over 40 years of age you may benefit from a combined procedure that can simultaneously correct presbyopia (to learn more about presbyopia please refer to the chapter presbyopia).
2/ LASIK (Laser Assisted In Situ Keratomileusis)
LASIK is a mixed technique combining two lasers, a femtosecond laser followed by an excimer laser.
3/ PRK (Photo Refractive Keratectomy)
The procedure is quite the same but instead of creating a flap inside the cornea, the excimer beam energy is delivered on top of the corneal surface after its superficial layer (epithelium) has been peeled.
4/ INTRA OCULAR LENSES
Astigmatism can be associated with high-degree myopia or hyperopia. These refractive errors can be fully treated with the use of intraocular toric implants. The procedure consists in placing an additional lens either inside the eye in front of the human lens or after the latter’s extraction in order to correct the complete refractive error. The power of the implant is chosen based on the desired correction, and the accuracy of the result is excellent. Both the size and power of the implant are determined on a customized basis, depending on the preoperative measurements.
The procedure is performed under local anaesthesia (by drops) in an outpatient facility, and rarely exceeds one hour for both eyes. The visual recovery is very fast, as LASIK, rarely exceeding 24 hours, and allows the patient to resume a normal life the day after surgery. The advantage of this technique is also its reversibility, along with the possibility of resorting, if required, to another type of surgery several years down the road.