Is it not recommended/ unusual for a patient in their early 20s to undergo lens replacement surgery (CLE) for their high myopia or is it okay and safe and not related to age?
It
can be done but I would not recommend you do it. There are several reasons:
1) There is considerably more
risk in doing an IOL procedure than LASIK.
2) There are other, less
invasive options ( even when LASIK is not an option) such as the ICL
3) No IOL yet developed can
match the quality of distance vision provided by the natural lens in a young
person.
4) Your young lens has a
tremendous ability to accommodate (change your focus to up close) which would
be lost
5) While there are many high quality presbyopia-correcting IOLs, none of them can match the quality of the young natural lens
I
perform many presbyopia-correcting IOL procedures every week as well as LASIK
and ICLs. But I would strongly discourage at your age from having this done.