The research covers an eight year period from April, 1963, to January, 1971, and the data report the results of 6,580 tonograms taken on 2,396 patients 40 years of age and over. The report contains a description of the clinical technique of the use of the Mackay-Marg Electronic Tonometer. It establishes criteria for determining patients who are glaucoma suspects, criteria for referral, and criteria for positive diagnosis of glaucoma. It describes the method used to collect the data, a statistical analysis of the data and a discussion of the routine use of tonometry in an optometric practice. The data establish that the incidence of glaucoma increases directly with age.