Absolutely! 6/6 vision is possible in the context of high myopia. The best way to know your visual potential is to have an accurate spectacle refraction performed. If you can attain perfect vision with the use of spectacles or contact lenses, then refractive surgery has a good chance of giving you similar vision without the need for such visual aids.
Instead of wearing a negative lens to correct your vision, laser refractive surgery uses an excimer laser to reshape corneal tissue by "removing" a positive lens from your cornea. This procedure is permanent and highly predictable, so 6/6 vision is definitely attainable.
