Well, generally speaking, subconjunctival hemorrhage in some serious cases can lead to blindness. First, you should know that subconjunctival hemorrhage is similar to an ordinary bruise on the skin and it's like a bruise of the eye. It usually appears as a single, concentrated spot of red, or many scattered red splotches, on the white of the eye. In many cases, it can be harmless. And it can disappear by them. But on the other hand, you should know that because they are related to the bleeding in your eyes, so it can lead to blindness, if the situation becomes worse. So if you suffer some bleeding in your eyes because of subconjunctival hemorrhage, it can be an alarm. So at this moment, you must go to hospital and see an eye doctor as soon as possible, or it will be dangerous.
Yes, subconjunctival hemorrhage can cause blindness. Though most subconjunvtival hemorrhage doesn't affect eyesight, you have retinal bleeding which is because of diabetes and that will lead to blindness. Moreover, if the hemorrhage is localized, the only way to treat it is to operate laser surgery. And if the vitreous humor has become clouded by blood, you will need an operation called a vitrectomy to replace the natural fluid with a clear, saline solution.
You should know that subconjunctival hemorrhage is one of the most complicated problems related to eyes, because it simply scratched the retinal of your eyes. I mean, if your subconjunctival hemorrhage is not properly taken care of and cured, and there is a lack of treatment and clinical care, then you might suffer blindness. So you need to take some immediate measures before things go wrong. Hope you recover as soon as possible.