Measurement of intraocular pressure (IOP) (tonometry) is conducted rou
tinely in the eye clinic for the diagnosis and management of primary o
pen-angle glaucoma. Mean IOP may be influenced by a number of factors
including ocular accommodation, spontaneous pulsations of IOP, and the
effect of repeated applanation. A review of some of the factors that
influence IOP should help us gain a perspective on the reliability of
diurnal tonometry in the diagnosis of primary open-angle glaucoma.