What eyeshade rules apply?

All players must wear opaque eyeshades at all times, so that no one can see regardless of their level of vision. This lets athletes with complete and partial blindness compete on equal terms. Touching your eyeshades during play is a penalty.

Sources: https://canadianblindsports.ca/goalball/about-the-game/ and https://ibsasport.org/sports/goalball/about/overview/