GI glasses
GI glasses are eyeglasses issued by the American military to its service members. Dysphemisms for them include the most common "birth control glasses" (BCGs) and other variants. At one time, they were officially designated as regulation prescription glasses (RPGs). This was commonly said to mean "rape prevention glasses" due to their unstylish appearance. At times in the US Navy they were called "Standard Navy Ugly Glasses" (SNUGs). Similar glasses (without metal) can be issued to inmates in state and federal prisons.