Praise be to Allah.
There is nothing wrong with the fasting person using ear drops and eye drops , and his fast is not invalidated by that.
Some scholars are of the view that ear drops invalidate the fast if the taste can be felt in the throat. So in order to be on the safe side, it is better to avoid that during the day in Ramadan, and if the one who feels the taste in his throat repeats that fast, then that is better.
It says in a statement of the Islamic Fiqh Council:
“The following things are not regarded as breaking the fast: eye drops, ear drops, having the ears syringed, nose drops and nasal sprays , so long as one avoids swallowing anything that may reach the throat.”
Shaykh ‘Abd al-‘Aziz ibn Baz (may Allah have mercy on him) said:
“Cleaning the teeth with toothpaste or a siwak does not invalidate the fast, but the fasting person must avoid letting any of that reach his stomach, but if it happens without him intending it to, then he does not have to make up the fast. The same applies to eye drops and ear drops. They do not break the fast according to the more correct of the two scholarly opinions, but if he finds the taste of the drops in his throat, he should make up the fast in order to be on the safe side, but it is not obligatory, because these are not openings through which food and drink enter the body. But nose drops are not permissible, because the nose is an opening through which food and drink may enter the body. Hence the Prophet (peace and blessings of Allah be upon him) said: “Snuff water up into the nose deeply, unless you are fasting.” (Narrated by al-Tirmidhi (788) and Abu Dawud (142); classed as sahih by al-Albani)
The one who does that has to make up the fast because of this hadith and similar reports, if he finds the taste of that in his throat.” (Majmu’ Fatawa al-Shaykh Ibn Baz, 15/260, 261)
He also said:
“The correct view is that drops do not break the fast, although there is a difference of opinion among the scholars and some of them said that if the taste of them reaches the throat then they do break the fast. But the correct view is that they do not break the fast at all, because the eye is not an opening through which food reaches the body. But if the one who uses them and finds the taste of that in his throat repeats the fast in order to be on the safe side and to avoid an area of scholarly difference of opinion, there is nothing wrong with that. But the correct view is that they do not break the fast whether they are eye drops or ear drops.” (Majmu’ Fatawa al-Shaykh Ibn Baz, 15/263)
Shaykh Muhammad ibn Salih al-‘Uthaymin (may Allah have mercy on him) said:
“With regard to eye drops – and also using kohl – and ear drops, they do not break the fast because there is no report to indicate that, or anything mentioned in the reports that suggests that, and the eye is not an opening through which food and drink enter the body, and neither is the ear.
The scholars said: If a man stains his feet with colocynth (bitter-apple) and notices the taste of that in his throat, that does not break his fast, because that is not an opening through which food and drink enter the body. The same applies if he uses kohl or puts drops in his eye or his ear: it does not break his fast even if he notices the taste of it in his throat. Similarly, if he applies ointment for medical purposes or otherwise, it does not affect him. And if he has difficulty in breathing and uses this puffer in his mouth in order to make his breathing easier, that does not break his fast, because it does not reach the stomach, and it is not food or drink.” (Fatawa al-Siyam, p. 206)
And Allah knows best.