Sheikh Salman al-Oadah
The Prophet (peace be upon him) said: “Allah has cursed the woman who adds extensions to her hair and the woman who asks for it to be done.” [Sahîh al-Bukhârî (5934) and Sahîh Muslim (2122)]
This is referring to extensions of hair being added to the hair on the head.
It is not apparent from the evidence that false eyelashes or eyelash extensions come under the prohibition.
Therefore, if a woman has short or sparse eyelashes and finds that wearing false eyelashes enhances her beauty or boosts her self-esteem, then there is no problem with her doing so.
Otherwise, it might be better to avoid the practice.
And Allah knows best.
Source: Islam Today