Is there a way to solve this?
Your balance does not only rely on your inner ear, but also on your eyes making out a fix point - preferably not too close, and stable - not the other person also struggling with the pose. You can easily test this with far easier poses, like standing on one leg, with eyes open or closed. So that the pose is hard to do with eyes closed is expected.
Depending on your reasons for wanting to do the pose with eyes closed, you can do the following:
Disclaimer: I'm not a yogi, I don't think I could hold any one legged pose with my eyes closed, and all this is just common sense and knowledge aquired here and there.