The federal government has upgraded its investigation into older model Nissan Altimas after 75 people said they were hurt by the force of a deploying air bag. Most suffered facial injuries, including 32 who had eye damage after the passenger-side air bag deployed in a crash. At least one person lost an eye. Most of the injured passengers said they were wearing seat belts. A spokeswoman for Nissan North America Inc. said they may not have been sitting in the proper position or may have had an object in front of their eyes, such as a soft drink can or their hand. The investigation involves about 248,638 vehicles from the 1994 and 1995 model years.