Here are some Prophetic Ahaadith on the use and health benefits of kohl for the eyes. They are taken from the great work “Healing with the Medicine of the Prophet (sallallaahu ‘alayhi wasallam)” by the noble scholar Ibn Qayyim Al Jawziyyah.
Ibn Abbas, radhiAllaahu ‘anhu, narrated:
“Whenever the Messenger of Allaah, sallallaahu ‘alayhi wasallam, used to wear kohl, he would use it thrice in the right eye -beginning with it and finishing with it – and twice in the left eye.”
Also, Abu Dawud narrated that the Prophet, sallallaahu ‘alayhi wasallam, said:
“Those who use kohl should use it an odd number of times.”
One should use an odd number of times when applying kohl in both eyes, thrice in the right and then twice in the left eye. Or, one should use the kohl thrice in each eye, as Imam Ahmad has stated.
Kohl preserves the health of the eye, strengthens and clears the sight and removes harmful substances, along with adding a touch of beauty to the eye. When one uses kohl before he goes sleep, it is beneficial for the eye, especially since the eyes will not be moving and thus the kohl will have its most favorable affect. The Ithmid type of kohl is especially effective in this regard.
Ibn Majah narrated in his Sunan that ‘Abdullah bin ‘Umar, radhiAllaahu ‘anhu, related from the Prophet, sallallaahu ‘alayhi wasallam, that he said:
“Use Ithmid (antimony), because it clears the eye and grows the eyelashes.” [Al Hakim]
Also, Ibn Majah narrated in his Sunan that Ibn ‘Abbas related from the Prophet, sallallaahu ‘alayhi wasallam, that he said:
“The best of your kohl is the Ithmid (antimony), because it clears the sight and causes the eyelashes to grow.” [At Tirmidhi, Ibn Majah, Ibn Hibban, Al Hakim, At Tabarani and Abu Na'im]