A visual acuity worse than 20/30. The determination on examination by the examiner that the lens opacity alone defines the vision. For individuals less than age 65 the nuclear cataract will be denser than NO2, NC2 or contain other components (posterior cortical or posterior sub capsular) that will be documented. For individuals 65 years of age or older, the nuclear cataract will be greater than NO3, NC3 or contain other components that define the vision.