Imam Malik (may Allah have mercy on him) said that it reached him that Sayyidah Umm Salamah (may Allah be pleased with her), the wife of the Prophet (peace and blessings be upon him), said to a woman who was mourning her husband, whose eyes were ailing and it had become severe for her: "Apply kohl al-jala' at night and wipe it off during the day."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب العدد / 15536