If by 'longsightedness' you mean 'presbyopia' or in Chinese 'Lao Hua', then LASIK is not a method that can treat this no matter whether someone had prior correction for myopia or not.
Again, LASIK is not and cannot be used to treat presbyopia per se.
You might find prior answers to this related question interesting: https://www.human.com.sg/questions/is-it-possible-to-go-for-lasik-again-if-i-now-have-presbyopia
On the other hand, if someone did unexpectedly develop true longsightedness (hyperopia) some years after LASIK, it is usually possible to retreat/enhance with a second LASIK to correct the hyperopia. This can usually be done by relifting the original LASIK flap, or alternatively by performing a surface ablation/epiLASIK/PRK type procedure.
