Yes. It is harmful for eyes to stare at the sun. It is extremely dangerous if you often staring at the sun, it may even cause permanent damage to the eye. You know that the sun carry ultraviolet rays that can contribute to cataracts for long run. Besides, the strong sunlight will cause your eyes feel burning. So, for your eye sake, you shall try not to star at the sun.
No, in fact, staring at the sun do not cause permanent damage to eyes, especially retina of your eyes. Each of us is different, the angle of the sun, the amount of clods and other variables come into play. But it would increase the wrinkle around the eyes when you exposure under the sun for a prolonged period. Due to the strong UV light would accelerate the development of cells. When you directly stare at the sun without wearing sunglasses, you would feel too bright to open your eyes. That is to say, you would close your eyes to prevent bright light to enter your retina to cause any natural damage
I persuade you not to stare the sun directly, it will really do harm to your eyes. The strong rays and ultraviolet will stimulate your retina; they will burn your eyes. The strong rays will damage your eyes, but you will never have something feel discomfortable, that is because there have no sense of pain in the retina. The burning degree will relate to the staring time and level of rays. After the staring at sun, the vision will decrease, even distortion of the image, the most serious one is blind. Some damage would be recovery, and others will be permanent visual injury. Some people get eyes damage when they observe the solar eclipse, that is a strong evidence for the harm of sun rays.
Yes, staring at the sun directly is harm for the eyes. If the sunlight is strong, its uv and other bad lights may stimulate your eye nerves which may affect your vision. You'd better not do this. But you could wear the sunglasses to look at the sun directly which may protect your eyes from the uv and other damaging lights.