Diurnal intraocular pressure patterns are not repeatable in the short term in healthy individuals

Purpose: To evaluate the short-term repeatability of diurnal intraocular pressure (IOP) patterns in eyes of subjects without glaucoma.

Design: Observational cohort study.

Participants: Forty healthy subjects without glaucoma.

Methods: Subjects underwent 12-hour diurnal IOP assessment sessions from 8:00 am to 8:00 pm on 2 visits 1 week apart. Intraocular pressure was assessed by Goldmann applanation tonometry. An analysis was performed to determine the agreement of individual diurnal IOP patterns from the first visit to the second visit. The intraclass correlation coefficient (ICC) was used to analyze both agreement of IOP values at each time point between visits and IOP change over periods between time points between visits.

Main outcome measures: Diurnal IOP patterns.

Results: Between-visit agreement of IOP values at each time point generally was fair to good, with ICCs ranging from 0.37 to 0.62 in right eyes and from 0.35 to 0.71 in left eyes. Between-visit agreement of IOP change over time between time points was uniformly poor and often below that expected by chance alone, with ICCs ranging from -0.25 to 0.15 in right eyes and from -0.40 to 0.22 in left eyes.

Conclusions: Eyes of healthy individuals do not manifest a sustained and reproducible diurnal IOP pattern when measured by Goldmann tonometry. A single-day assessment of IOP incompletely characterizes the diurnal IOP pattern.