But I have found couple methods to open my eyes. First one was when I realised it was hard to open my eyes and by forcing them to open I was afraid I'd force myself awake. So I covered my head with a bed cover and opened my eyes in a complete darkness.
Unfortunately thinking of a body part and moving it is the normal way to get out of sleep paralyses if one wants to wake oneself up (most will think of a finger or toe to break the state but thinking of moving eyes can do same thing) so for many this will wake the person up as they may twitch real eye when trying to force a dream one to move. So its often better just to be patient and ignore blindness for a bit as the sight WILL come in itself if people dont let not being able to see bother them and keep thinking about being blind (as when dreaming you often create what you think, best not to focus on it for that reason too).
I forgot to add to my other post that those who do OBEs sometimes experience blindness if too close to their physical bodies, In this case just moving into another room so away from ones body will usually have the vision naturally come in.