The blood clot in your eyes may be caused by your large amount of use of eyes in front of the computers or other electric products. Or the eyes infection may cause the blood clot in the eyes, too. You could firstly use the eye drops to release the symptom. If it is not worked, you could go to the hospital to accept the medical treatment.
Actually, a sub-conjunctival hemorrhage, and high blood pressure, stressing to the eye, and many other things can cause blood clot of your eyes. However, it will heal by itself. If you feel pain, you need to take some measures, such as using eye drops and don't scratch. When you go out, you need to wear sunglasses.
Well, generally speaking, a blood clot in the eyes can be dangerous. You should know that it appears as a single, concentrated spot of red or many scattered red patches on the white of the eyes. And in common, some eye injury, high blood pressure, even other eye disorder can lead to it. So you should pay more attention to it, or it can be serious. To treat it, you can try some ways. For example, you can just put a hot compress over the eyelid to get relief from irritation. Or just console it with the doctor, and he can give some advices. And when it occurs, you may suffer eye pain too. Of course, other symptoms, such as blurry vision, even red eyes can occur.