Bulugh al-Maram #776

'A’isha (RAA) narrated, The Messenger of Allah (ﷺ) applied kohl to his eyes while he was fasting.’ Related by Ibn Majah with a weak chain of narrators. According to At-Tirmidhi, nothing authentic has been related from the Prophet concerning this issue, i.e. applying kohl, eye drops etc. to the eye while fasting.