All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.
Contemporary scholars held different views on the permissibility of cutting the eyelashes; some deemed it allowable on the account that there is no clear prohibition reported in this regard and the fact that cutting the eyelashes does not fall under the category of the prohibited nams (plucking the eyebrows) about which the Prophet warned, cursed the one who does that for someone or lets someone to do it for him and labeled such an act changing the creation of Allaah, which is prohibited.
A question was sent to the Fataawa and Consultations on the "Islam Today" website reading, "What is the religious ruling on defining the eyelashes and trimming them for women? Does it fall under nams?"
The answer reads
"Praise be to Allaah alone; may blessings and peace be upon the last Messenger. Indeed, Allaah, The Exalted, created man in the best form and honored him, granting him preference, honor and respect over all other creatures. It is impermissible to change the way man was created because this constitutes changing the creation of Allaah, The Exalted, as if the doer is not pleased with the way Allaah has created him! Therefore, it is prohibited for a Muslim man or woman to change the creation of Allaah by enhancing eyelashes for women by means of lengthening, shortening, or separating them. Such an act is deemed prohibited because ʻAbdullaah ibn ʻUmar narrated that the Prophet said, "Allaah has cursed the lady who artificially lengthens someone else's hair and the one who gets her hair lengthened and the one who tattoos someone else and the one who gets herself tattooed." [Al-Bukhari: 5937, Muslim: 2124] The act of artificially lengthening the eyelashes is similar to using hair extensions and both are prohibited. Ibn Masʻood narrated, "the Prophet forbade women from plucking the eyebrows, filing the teeth, artificially lengthening the hair, or having tattoos except due to illness." [Musnad Ahmad: 3945, and others] Therefore, it is impermissible for the Muslim to change the creation of Allaah except in the case of a physical deformation due to an accident or an illness; in this case, it is permissible to treat such deformation. This act does not come under the heading of changing the creation of Allaah rather it is only meant to recover the original condition of the deformed body part, which is permissible. Verily, Allaah knows best."
"It seems that there is no religious impediment to trimming the eyelashes because the sharee'ah does not forbid it and it does not fall under the heading of the prohibited nams because the nams particularly refers to the removal of the eyebrows either by shaving or plucking. There is a clear difference between trimming eyebrows and trimming eyelashes; changing the eyelashes does not alter the appearance of the person the way changing the eyebrows does. Moreover, cutting the eyelashes does not constitute changing the creation of Allaah because it is not permanent and therefore the relevant ruling on permanent changes made in any other part of the body does not apply in this case ... Trimming the eyelashes is allowable on condition that there is no harm or health risk incurred as a result and that they are not cut in a way that disfigures the face or constitutes prohibited disfiguring or changing Allaah's creation..."
Allaah knows best.