Single intraocular pressure measurements and diurnal intraocular pressure profiles.

Abstract

To evaluate the probability of a single intraocular pressure measurement to be the highest measurement within a diurnal intraocular pressure profile. Hospital-based clinical, observational study. The study included 3,025 day-and-night intraocular pressure profiles measured on 1,072 eyes of 547 Caucasian glaucoma patients or glaucoma suspects. Applanation tonometry was performed at 7 am, noon, 5 pm, 9 pm, and midnight. Intraocular pressure measurements were highest at 7 am, noon, 5 pm, 9 pm, and midnight, respectively, in 20.4%, 17.8%, 21.3% 13.9%, and 26.7% of the profiles, respectively. The measurement taken at 7 am was significantly (P < .001) closest to the maximal value of the profile. Any single intraocular pressure measurement taken between 7 am and 9 pm has a higher than 75% chance to miss the highest point of a diurnal curve. Intraocular pressure may be measured at different times of the day to have the best chance of observing the maximal value.