The time has come when the accent on blindness prevention must be placed where it rightly belongs; on the two greatest causes of blindness in the United States, chronic glaucoma and amblyopia ex anopsia. Since the problem is primarily one of detection, both of these conditions are preventable to a large degree. Considerable information has accumulated recently indicating that chronic glaucoma is commoner than is generally realized. Mass screening, by Brav and Kirber,1of 10,000 persons employed in Philadelphia industries revealed a 1.53% incidence of undiscovered glaucoma in the age group 40-65 years alone. These authors estimate the incidence of undiscovered glaucoma in the general population at 2%. The more recent Cleveland Glaucoma Survey2indicates exactly the same figure in a free screening of about 14,000 persons. Zeller and Christensen,3working in Portland, Ore., found the same incidence in a somewhat smaller series. These authors point out