Intra-ocular pressure, glaucoma, and glaucoma suspects in a defined population

Abstract

The aims and methods of a total population study of intra-ocular pressure, glaucoma, and glaucoma suspects are described. Applanation pressure in non-glaucomatous persons is skewed to the high side of the mean. The distribution is affected by: (1) Age (2) Sex (3) Time of day (4) Digit preference (5) Decision effect Schiötz pressure distribution is distributed bimodally if low scale division readings are avoided by changing weights. This bimodality is an artefact. The distribution is affected by: (1) Age in females but not in males (2) Sex (3) Time of day The meaning of normal and average intra-ocular pressure is discussed and a plea made for the consideration of pressure variations from normal to abnormal as a continuum. The glaucomas are defined. The prevalence is given in the population studied of: (1) Chronic simple glaucoma (2) Low tension glaucoma (3) Angle-closure glaucoma (4) Congenital glaucoma (5) Secondary glaucoma The age and sex distribution of persons with chronic simple glaucoma and low tension glaucoma is given. Chronic simple glaucoma suspects are defined and described in three groups: (1) Ocular hypertensives (2) Persons with enlarged optic cups (3) Persons with pseudo-exfoliation of the lens capsules Actuarial aspects of the relationship between ocular hypertension, tonographic abnormalities, and chronic simple glaucoma are described. Prevalence rates for each group of glaucoma suspects are given. Comments are made on the present position of predicting the clinical fate of these suspects. The need for long-term prospective follow-up studies is stressed.