Air sandwiched optical discs with closable pressure relief holes

An optical disc is disclosed having a substrate in which data can be written on or read from, such optical disc being adapted to be inserted and clamped onto a spindle in a disc drive and having a transparent cover sheet disposed over the substrate surface. The cover sheet is held at inner and outer radii so that it is positioned to have a desired spacing from the substrate to prevent contaminants from passing to the substrate surface. A plurality of air passages are formed in the optical disc to prevent the transparent cover sheet from deflecting due to pressure differences between the outside atmosphere and the air in the space between the substrate surface and the transparent cover sheet.