There is no blame upon the person who is fasting if they use kohl so long as it is not felt in the throat. If it can be felt in the throat, then the day of fasting should be made up just to be on the safe side and it is better if the person who is fasting avoids using kohl during the day while they are fasting. (Part No. 10; Page No. 254) May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.