There is no default eyelash replacement, and people seem happy with the mods currently available. Also, having default eyelashes may mean that your sims may have a look which isn't quite your aesthetic.
http://cienzroza.blogspot.com/2017/...ttle-thing.html
Download and unzip
I use the No EA eyelashes mod unmerged - pop the four package files (age groups) into your mods folder. NEVER put these through sims4studio. they will break. there will be unhappiness. been there done that.
pop over to Kijiko:
http://kijiko-catfood.com/3d-lashes...mber-23th-2018/
the first two downloads, once extracted and put into your mods folder will be found in CAS - ACCESSORIES - GLASSES
the second two downloads, once extracted and put into your mods folder will be found in CAS - Body - SKIN DETAILS.
other lash styles are also available by Kijiko on that same page (scroll down) (I don't use), but you can use as many or as few as you want. If you use the first sets that I listed above, that would probably be satisfactory.
Some skin details don't show up with certain custom skins.
and accessory eyelashes won't let you wear glasses as well.
I hope that helps.