There are 3 main types of lasers:
- surface ablation (aka PRK, epi-LASIK, LASEK)
- LASIK
- and Relex SMILE.
All 3 are able to correct levels of astigmatism of about -4.00.
However, the degree of astigmatism isn't the only limiting factor. More importantly, we also have to consider corneal shape and thickness. All factors are important for consideration before the surgeon decides on what is best for you in terms of safety as well as stability of the cornea after the lasers.
For example, one may have sufficient corneal thickness and low levels of astigmatism, however, should the shape of the corneal be indicative of a higher risk of instability after the lasers that may lead to complications, lasers may not be recommended at all.