Well, of course no. sperm in your eyes will not cause blindness. So you do not need to worry about it. And generally speaking, there are many reasons which can just lead to blindness, such as retinal detachment. But on the other hand, there is nothing to do with sperm. On the other hand, sperm in your eyes can just lead to eye infection in some cases. At that time, your eyes will just feel red, and itchy. So just try some ways to avoid eye infection.
You will not get blindness because of the bit of sperm in the eyes. Your eyes may be stimulated for a while. You should wash the eyes carefully with the clean water. Then you could use the clean cloth and hot water to do the warm compress to release the symptom. Your eyes will be ok. You should not let the sperm into your eyes next time.
Well, looks like there is some slight problem with your eyes. As far as I know, sperms does not contain any bacterium, thus, they are not infectious to our eyes. However, such stuff would inevitably lead to some irritations to our eyes and make them uncomfortable. Therefore, you also need to flush your eyes with some clean water or get some eye drops to deal with that.