In the sunnah of Prophet Muhammad(peace be upon him) use and encouragement of the use of kohl(surma) is mentioned. In a number of hadeeths it is narrated that the Prophet (peace and blessings of Allaah be upon him) used kohl and commanded others to do so. It is narrated in the Musannaf of Ibn Abi Shaybah, from the hadeeth of Anas, that the Prophet (peace and blessings of Allaah be upon him) used to apply kohl to his right eye three times, and to his left eye twice. This hadeeth was classed as saheeh by al-Albaani in al-Silsilah al-Saheehah no. 633. And it was proven in Sunan al-Nasaa’i (5113) and Sunan Abi Dawood (3837) and elsewhere, from the hadeeth of Ibn ‘Abbaas (may Allaah be pleased with him) that the Messenger of Allaah (peace and blessings of Allaah be upon him) said: “The best of your kohl is ithmid(antimony), for it makes the vision clear and makes the hair grow.”
Kohl protects the health of the eyes and gives the vision the strength and clarity. It cleanses the eyes of bad vision and bad substances. In addition to that some types of kohl also serve as an adornment and if it is applied before going to bed this is even better. And ithmid is more efficacious than other types of kohl.
It says in al-Mughni: It is mustahabb to use kohl an odd number of times. (al-Mughni, 1/106).
With regard to using kohl an odd number of times there is a difference in opinoins of various scholars. Some are of the opinion that it must be applied odd number of times to one eye and even number of times to other eye so that the total number will be odd. However correct view of the scholars who examined this issue is that it must be applied odd number of times to each eye which is the sunnah of Prophet Muhammad(peace be upon him).
Some eye doctors say that kohl is harmful to the eyes and they advise not using it. However, this is not true. Ithmid(antimkny( is known to be very beneficial to the eyes. One should consult trustworthy doctors and consult them in this matter.
And it was said of Zarqa’ al-Yamaamah, who could see as far as three days, that when she was killed, they saw that all the veins of her eyes bore traces of this ithmid.
(Majmoo’ al-Fataawa, vol. 17; Chapter on medical treatment and visiting the sick).
From the above discussion we come to know that kohl(surma) is better for eyes and not harmful at all. There may be some kinds of artificial, manufactured chemical versions of kohl that can cause damage and may not be as beneficial.
Hence people nowadays should look for pure kohl and not regard every kind of kohl available nowadays as beneficial.
Also instead of using chemical cosmetics that harm the eyes, one should opt for the natural and beneficial one.
And Allaah knows best.