In the present study a large group health population was selected as a normal population. A random sample of this parent population was studied by Goldmann's applanation tonometry and by the Schiotz method. After tonometry, tonography was performed on a group of glaucoma suspects and an appropriate control group.
A large group health population of approximately 20,000 patients was studied.* This group is composed of 95% white and 4% colored patients from the Bronx borough of New York City. It comprises the following employment groups and their families: Board of Education 17%, Police and Fire Department 14%, Transit Authority 14%, Other City of New York Employees 20%, Trade Unions 16%, Other 19%. There is approximately an equal number of males and females. The percentage distribution by age is as follows: between 14-20 years 6%, between 20-39 years 23%, between 40-59 years 33%, over 60 years 12%, unknown age 2%.
LEVENE RZ. Tonometry and Tonography in a Group Health Population. Arch Ophthalmol. 1961;66(1):42-47. doi:10.1001/archopht.1961.00960010044010