It is not possible to "save" during the middle of a session and continue later on. This is because of the games Arcade style of play - you play through all 10 levels trying to rank in the high score...
To get glasses in Star Fox 64, the Nintendo 64 game, you have to do the hard rought, which is Cornaria, Sector Y, Aquis, Zoness, Sector Z, Area 6, and Venom, and then Fox McCloud will have glasses.