"Leah had weak eyes." Like (the verse), "weak and anointed (for war?)." (2 Samuel 3:39) Another interpretation: From how people would say to Laban that his two daughters and Isaac's two sons, that the old should marry the older, and the younger marry the younger. And Leah would go out to the crossroads and ask passersby about Esau's deeds. They would tell her what a completely wicked person he is, and how his younger brother is a mild mannered man. And Leah would cry because she was the oldest (and would have to marry Esau), until her eyes became tender.