In order to understand how lasik works we first need to understand how a human eye works.
The Human eye works like a normal camera. Light rays travel through the Cornea ( front surface of eye), the Lens in the middle portion and are then focused onto the Retina (back surface of the eye).
Spectacles /Contact Lenses are required when size and shape of the eye doesn’t correspond to its focusing power meaning they don’t focus on the surface of Retina.
In case of Myopia/Near Sightedness/Minus Power light rays are focused in front of the Retina
In case of Hypermetropia/Farsightedness/Plus power light rays are focused on back of the Retina
In case of Astigmatism/Cylindrical Power they are irregularly focused
LASIK Procedure uses tiny laser spots and multiple locations over the cornea to reshape the corneal surface in such manner that light rays are focused precisely onto the retina , hence removing the need for any spectacles or contact lenses