If I Close My Eyes In A Tanning Bed... Do You Absolutely HAVE To Wear Goggles In A Tanning Bed?

Do you absolutely HAVE to wear goggles in a tanning bed? - if i close my eyes in a tanning bed...

I have tanning beds more than a month and I understand that you can almost see the white circles around the eye glasses. They are not very sensitive, and I can not stop it with my makeup, but I wonder if I could close my eyes in bed instead of the glasses disappear him, or is not a good idea?