Although the incidence of blindness in the United States is the lowest of any major nation (54 per 100,000), preventable blindness still occurs far too frequently. Despite the efforts of the ophthalmologists, the general practitioner, and the public health workers, there are now 17,000 legally blind persons in Ohio—enough to populate a small city. Improvement of these statistics of tragedy would be possible by application of existing knowledge through earlier detection and treatment of serious eye diseases.
A proven and fruitful method for early detection of serious disease is the widespread use of well-chosen screening procedures. The objective of a screening procedure is not to diagnose disease but to detect persons who are likely to have disease, in order to permit referral for definitive study and care. The ideal screening method should not fail too many normal persons (false-positive result) and, more important, should not overlook any case of disease
CASSIDY V, HAVENER WH. Evaluation of a Screening Procedure in the Detection of Eye Disease. AMA Arch Ophthalmol. 1959;61(4):589-598. doi:10.1001/archopht.1959.00940090591014