[tousuarshatly]

Instruction in zazen practice has convinced me to keep my eyes half-open, half-closed. I was taught that the practical reasons for this are generally twofold: (1) to prevent dozing off and avoid tuning out the external world, as might happen sometimes with eyes closed, and (2) to limit the tendency of the eyes to roam out of boredom in search of something exciting, which can occur with eyes wide open.

After a couple of years at it, I've noticed that eyes fully open and eyes fully closed both have their drawbacks. Fully open has the drawback of sensory stimulation becoming quite the distraction. Fully closed has the drawback of mental stimulation becoming quite the distraction. With eyes neither fully open nor closed, softly focused and directed a few feet in front of one's seat, I feel I've found a middle point that works well for me.

It took me a while to acclimate to having eyes half-open, half-closed. My eyelids would flicker at first, but it was primarily because I was exerting small amounts of muscular effort to keep my eyes from closing while at the same time preventing them from being fully open. In retrospect, I was actually squinting. There's no need to squint to achieve the half and half state. Just let the gaze soften and the eyelids will naturally relax.

However, when I do vipassana, my eyes are closed. The eyes-closed state helps me in noting the changes the body and mind experience from moment to moment.

Experiment with different methods to see what works best for you.