In yoga postures, where to look and perspective is very important.
Many yoga teachers will tell you where to look in each posture. Basically you should avoid looking around to see what other people’s postures are doing and neglecting your own.
Closing the eyes completely is also not recommended unless you are very advanced. If you can keep the balance super stably to close the eyes in tree pose for five minutes, you may be able to close the eyes in other postures, but the basic idea is to look where you need to look and focus on the postures.
By scanning every part of the body, By making sure you are aware of everything, By observing carefully and bridge the gap between what you are trying to do (ideal) and what you are actually doing (reality). By looking more inside yourself, you can deepen the postures with new insights.