Is it harmful to the eyes, to stare directly at a bright full moon?

Staring directly at the moon, even when it's bright, is generally not harmful to your eyes. Andrew Huberman explains that moonlight, along with candlelight and fireplace light, does not reset your circadian clock or trick your brain into thinking that it's daytime. This is because the neurons in your eyes adjust their sensitivity across the day and respond primarily to the composition of light seen during sunrise and sunset, rather than the reflective light from the moon 1.

Overall, moonlight is considered low-intensity light. It typically won't have a significant impact on sleep disruption, even if the moon is very full and bright 1. Therefore, enjoying the sight of a bright full moon should be safe for your eyes under normal conditions.