It is so bad for you to get the bit of hydrogen peroxide into eyes which will cause your eyes to be red and swollen. You need to wash it out as soon as possible. In addition, you should also use some eye drops to clear the eyes and make them get bright. You could also use some warm compress to make your eyes be comfortable.
Generally speaking, the concentration of commercial hydrogen peroxide is only 3%. It will not do much damage to your eyes. But if you are still worried about your eyes you can wash your eyes with clear water for a few times. If you feel unsafe, you can have a little drops of eye drops. But if the hydrogen peroxide is not commercial hydrogen peroxide, you had better wash your eyes with a lot of water for several times and go to consult a doctor.
Yes, it is really harmful to your eyes.
You should lift your eyelid and wash your eyes with light brine for more than 15 minutes and see if your eyesight is affected or not. To ensure your eyes are OK, you need to see a doctor who can examine your eyes thoroughly.
Chances are that your eyes may get inflammation and burned, as hydrogen peroxide creates strong chemical reaction with other agents.
It is often used as disinfectant and antiseptic in lower concentration , so you can see how dangerous it is, not to mention how poisonous and unstable it is when in high concentration.