And he turned away from them, and said: “How great is my grief for Joseph!” And his eyes became white with sorrow, and he fell into silent melancholy.
Ibn ‘Abbâs explains the words Abyadzdzat ayna-hu as the filling of the eyes with tears (Râzî). It is wrong to translate this term as “his eyes became blind”. This expression is used for a person
who is stricken with grief and whose tears fill his eyes (Tâj). The Holy
Qur’ân lends no support to the view that Jacob had become blind
because of weeping. Jacob, though a prophet and trusting fully in
Allâh, was still a human being with passions and feelings of sorrow
and joy. He missed his son for many years, and it was only natural
that his eyes would fill with tears when his other sons returned
without Benjamin. Jacobs love for Joseph was all the stronger
knowing that Joseph was chosen by Allâh (cf. 12:6).
NOORUDDÎN ,ALLÂMAH. (2015). Exegesis of The Holy Qur’ân Commentary and Reflections. http://www.islamicweblibrary.com/wp-content/uploads/2020/10/Exegesis-of-the-Holy-Quran-Commentary-and-Reflections.pdf