Maliks Muwatta Book 29, Hadith Number 105.

Section : Limit of Abstaining from Adornment in Mourning.

Yahya related to me from Malik that he had heard that Umm Salama, the wife of the Prophet, may Allah bless him and grant him peace, said to a woman in mourning for her husband whose eyes were troubling her and the pain had become very strong, “Apply jala kohl at night and wipe it off in the day.”