For laser eye surgery, the length of the eye must be stable, while the shape of the cornea is corrected by the procedure.

“there's really three variables if you think about it there's the cornea the retina the the length of the eye i shouldn't say retina but the length of the eye and the lens itself so we know that the lens is going to continue to change throughout life but typically not until you're in your 50s 60s 70s when cataract formation will start to affect the light bending power of of the of the lens the cornea should not be changing that would be so you just have to make sure this length is fixed that's right”