I practice in the Soto tradition, facing the wall while meditating. I'm always told to not focus too much on the wall, but it seems to be second nature. I start staring hard then get real eye strain at the end. I don't know if there's any exercising a person can do with the eyes to make them more relaxed before meditation? If it gets too much I'll often close my eyes for a while, then likely fall asleep.