Doctor's Answers (3)
This is a very good question. Compared to patients with lower level of myopia, it is indeed true that high myopes are more likely to have regression after laser vision correction (LASIK, SMILE, PRK).
LASIK is known to have good predictable outcomes. However, studies had suggested that there is a higher incidence of regression amongst high myopes. One contributing factor may be that one’s cornea has to be thinned down much more when they have high myopia, and thus the residual cornea thickness is significantly lower than individuals who started with low or moderate myopia. This thinner residual corneal thickness may be more prone to regression.
But nowadays, one can have the option to include collagen cross-linking on top of their laser surgery. Collagen cross-linking aims to strengthen the cornea by activating the collagen fibres on the eye to cross-link, thereby strengthening the eye by 5 times post-surgery. This may have the potential to reduce the possibility of the cornea going back to its original shape/ regression.
Another type of refractive surgery to consider for high myopia will be Implantable Contact Lens. These lenses ware implanted into the eye and power of the lens is customised to suit individual visual requirements. They have the potential to correct up to -18.00 of myopia.
Factors contributing to this include the fact that the corneal shape is changed more for high corrections, and also because some very high myopes may not fully stabilise even when they get older.
Having said that, how high is high?
Different studies give different results, but it is my experience that most patients with myopia up to around -7D or -8D (700-800 degrees) still get very good results. Even if their risk of regression is somewhat higher than someone with 200 or 300 degrees of myopia, very few regress to the extent that they need to wear glasses again. In other words, if regression occurs it is usually in the region of 50-75 degrees, where distance vision is still not too badly affected.
Patients who are particularly concerned about this can consider simultaneous LASIK with corneal crosslinking, as there are now small studies suggesting that regression can be reduced with this extra treatment.
Patients with even higher degrees of myopia may want to consider options such as ICL surgery, especially if their corneas are thinner than average.
Unfortunately, the answer is yes. Patients with higher degrees of myopia are known to experience more frequent regression of their original myopic refractive error after Lasik refractive surgery.
This is likely related to residual cornea thickness after surgery, and also the larger degree of ablation (for higher degrees of myopia).
Fortunately, we have in recent years a proven treatment of riboflavin collagen cross-linking (commonly termed Lasik-Extra) that helps to prevent this from occurring. Do discuss these options with your Ophthalmologist prior to deciding on your refractive surgery!