What does the Torah mean when it writes that "Leah's eyes were Rachos"?
Rashi: When Leah overheard people saying that Rivka's older son would marry Lavan's older daughter, and Rivka's younger son, Lavan's younger daughter, she would weep uncontrollably. 1 And it was the constant weeping that affected her eyes and made them soft. 2
Targum Onkelos and Rashbam: It means that she had beautiful eyes. 3 Ha'Emek Davar
And pray that she not fall to the lot of Esav (Targum Yonasan).
Maharsha (Bava Basra 123a) - due to Leah's pain and tears (the gates of tears are never closed - Berachos 32b), Leah merited to marry Yakov.
And Chazal have said (Ta'anis 24a) that a Kalah whose eyes are beautiful, the entire body does not require examination. Da'as Zekeinim - Rachel's eyes hurt [after she married Yakov (PF)], for she was barren; she cried lest Yakov divorce her, and she fall to Esav.
Surely, this is because Yehudah would come from her (PF).
What is the difference between "Yefas To'ar" and "Yefas Mar'eh"?
Tosfos ha'Shalem (2): The former refers to the face. The latter is grace in the eyes of those who saw her.
Tosfos ha'Shalem (3): The former is beauty of stature and limbs.
Ohr ha'Chayim: Yefas To'ar is each detail by itself - the eyes, nose, neck
Why does the Torah mention that the Imahos were beautiful? "Sheker ha'Chen v'Hevel ha'Yofi"!
Kol Eliyahu: This is without Yir'as Shamayim, but if she fears Shamayim, "Hi Sis'halal" also for grace and beauty. 1 Similarly, Chachmah, Gevurah and wealth are attributes only if the bearer knows (fears) Hashem (Yirmiyah 9:22-23).
Mishnas R. Aharon 3 p.177: Yefas To'ar and Yefas Mar'eh apply also to spiritual attributes.