You may have heard that if you have a high prescription, laser eye surgery will not be able to help you, you may have even been to a consultation at some point and been told by a surgeon you are unsuitable for laser eye surgery, however this may not necessarily be true.
With advances in technology over the past ten years combined with our expertise, we are now able to safely treat much higher prescriptions than previously possible.
Laser eye surgery involves removing precise amounts of tissue from the eye to create a subtle change in the shape of the cornea, resulting in the refocusing of the eye and overall corrected vision. The higher your prescription the more tissue we will need to remove. As such, this requires the cornea to be measured and mapped in extremely fine detail. By doing this, this gives us an exact idea of how much tissue can safely be removed.
In addition, for the LASIK method of laser eye surgery, we use a femtosecond laser to create a flap. Whereas before, the thickness of this flap was variable, modern lasers allow us to achieve a target thickness within 5 microns of intended. Furthermore, the flaps now are super-thin which allow for more room to correct the prescription when moulding the underlying cornea.
If you undergo laser eye surgery it is important to note that with a higher prescription the chances of you needing a re-treatment or enhancement is increased. The reason for this is that with a high prescription a bigger change to the shape of your eye is required to correct your vision. The more you change the shape of something the more likely it is to behave in a more unpredictable way. Your eye will not revert back to your original prescription, only a fraction of this so the second time around the surgery is only a touch-up to ensure you achieve the best vision we can offer you.
The typical rate of an enhancement for very high prescriptions is in the region of 5-10%. This compares with a typical figure of 2% when treating more common prescriptions.
As the amount of tissue removed from the cornea of your eye is greater with a higher prescription it means that your cornea must be thick enough for us to safely perform the surgery. At our clinic, safety is paramount and we perform detailed tests to allow us to make a decision on the safety of the procedure before we offer it as a treatment. If laser eye surgery is not suitable, there may be alternative options for example the ICL (implantable collamer lens) or refractive lens exchange and these will be discussed with you at your consultation.