Ophthalmologic examinations for cataract, glaucoma, diabetic retinopathy, macular degeneration and visual acuity were performed on 2631 of the 3977 members of the Framingham (Massachusetts) Heart Study population still living in 1973-1975. The subjects ranged in age from 52 to 85 years. This monograph presents the detailed protocols and record forms for screening and diagnostic examinations, definitions of the specific abnormalities and characteristics used to screen for each disease, criteria for suspicion and diagnosis of diseases, detailed tables of the basic data from the study, evaluation of quality of the data, and discussion of selected findings. The tables provide data on the number and proportion of persons and of eyes with each type of abnormality and each disease, by age and sex. Where appropriate, the data are further classified by location of abnormality, severity, bilaterality and associated visual acuity limitation. The study was sponsored by the National Eye Institute.