Dolls with blinking eyes all have eyelashes built into the eye.  You can add to a blinking eye by gluing lashes on top of the existing lashes but many of the lashes stick straight out and are tough to replicate.  Dolls with stationary eyes have a lot more play when it comes to adding lashes as they are glued either at the very top of the eye or just under the eyelids.  This depends entirely if the doll is built to remove eyes frequently or if they are made to have eyes stay put.  Larger dolls (18" and above) often utilize human sized lashes which are trimmed down to the eye size.  This is often by removing length either from the fullest part of the eyelash or at the shorter edge of the eyelash near the nose.  Many lashes are not specifically sized for a particular doll and therefore need trimming or shaping to fit your doll.