Can lasik treatment results into better vision than spectacles if yes when?

No: Lasik generally provides vision that is similar to what you have with your glasses or contact lenses on.

Yes: I have seen this many times. Some forms of astigmatism respond much better to LASIK surgery than glasses. Also, many patients perceive better vision at the same visual acuity because there are no glasses artifacts in the vision. Custom LASIK can sometimes treat higher order optical aberrations that glasses don't. Strong glasses are very sensitive to position and optical center.