presbyopia: a reduced ability to focus on near objects caused by loss of elasticity of the crystalline lens after age 45
hyperopia: abnormal condition in which vision for distant objects is better than for near objects
organophosphate nerve agent: any of a series of nerve agents containing organophosphate compounds first synthesized by German chemists in 1936; in World War II the Germans tested them in concentration camps but not on the battlefield; Iraq is alleged to have used them against Iran and against the Kurds