Laser vision correction (LVC) in all its forms helps patients correct their refractive errors by way of changing the curvature of the cornea. The various generations of LVC do so in slightly different ways that present unique sets of pros and cons in each of them.
Advanced Surface Ablation (ASA), including PRK, TransPRK, Epi-LASIK and LASEK, is a great option in low degrees, thinner corneas and in patients who wish to avoid the risk of LASIK flap dislodgement due to their occupation or sport activities.
Femto-LASIK overtook ASA in terms of popularity primarily due to its speed of visual recovery and comfort. In addition, it has proven to be able to provide excellent results through a wider range of refractive errors compared to ASA. However, some eyes may not be eligible for LASIK due to insufficient corneal thickness or in patients wanting to avoid the risks of flap complications and dislodgement.
ReLEx SMILE developed through lessons learnt from both ASA and Femto-LASIK, tries to combine the advantages of both previous generations of LVC by having the speed of recovery and comfort of LASIK and the avoidance of flap-related complications offered by ASA.
Now that I have walked you through a brief outline of the various advantages and limitations of the above types of LVC, you would appreciate that any serious laser centre should have the ability to offer the entire range of techniques to customise the treatment not just to the patient but to each eye as well.
I do agree with Dr Por Yong Ming that it is not often that we have to resort to applying to 2 different techniques in the same patient.
An example of why this scenario might arise would be the need to maintain a healthy amount of corneal thickness in both eyes resulting, with ASA being applied to the eye with lesser available amount of cornea to laser as ASA causes less corneal thinning compared to both LASIK and ReLEx SMILE. However, do remember that ASA has a smaller range of correcting refractive errors than LASIK or ReLEx SMILE.
There are many other permutations of “combinations” treatments. Suffice to say, it is best you have your eyes properly assessed for LVC suitability and have your trusted surgeon discuss the treatment options that best suits your eyes.
Dr David Chan
