In this midrash, the Avot each make a wish to Hashem for an improvement in the world. I have a couple of kashes on Yitzchak's wish:
אָמַר לְפָנָיו רִבּוֹן כָּל הָעוֹלָמִים אָדָם מֵת בְּלֹא יִסּוּרִים
He said before Him, "Master of all the worlds, man dies without yissurin [i.e. having suffered in life to atone for his misdeeds]..."
Hashem then grants him this wish, that there should be yissurin in the world, and starts with Yitzchak Avinu by making him blind.
I have 2 questions on this:
What happened to the curses given to mankind after the sin in Gan Eden? They are specifically curses that life should be a life of difficulty and pain. E.g. man has to sweat and work hard to make food, women have to give birth in pain.
Yaacov Avinu proceeds to wish for illness in the world, but didn't we already see illness just now with Yitzchak, i.e. blindness?