Why Leah's Eyes Grew Weak From Weeping Over Esau

Another interpretation: Why was she hated? Not because she was uglier than Rachel; rather, she was as beautiful as Rachel, as it is said (Genesis 29:16): "And Laban had two daughters" — equal in form, in beauty, and in stature. Why then does it say (Genesis 29:17): "And Leah's eyes were weak"? Rather: when Rebekah bore Esau and Jacob, two daughters were born to Laban, Leah and Rachel. They sent letters to one another and made an agreement between themselves, that Esau would take Leah and Jacob would take Rachel. And Leah would inquire about the deeds of Esau, and she would hear that his deeds were evil, and she would weep at all times, saying: "Thus has my lot fallen to this wicked man." And on account of this her eyes became weak, as it is said (Genesis 29:17): "And Leah's eyes were weak."