My Eyes Gets Tired Whenever I Use iPhone

I don't know why but recently when I use iPhone, my eyes become really tired. It wasn't like this before. Even when I watch tv. It's not like I'm using iPhone for a long time since this started happening. What should I do?

Stop using your iphone?

Lower the brightness.

Eat carrots.

You should tell this to an eye doctor

It could be eye strain from looking at such a tiny screen combined with the bright light. See an eye doctor for an exam to ensure no other more serious happenings.
Your eyes are precious.