Comparing the Measurement of Diurnal Fluctuations in Intraocular Pressure in the Same Day versus over Different Days in Glaucoma

Abstract

Purpose.

To compare the measurement of diurnal fluctuations in intraocular pressure (IOP) in the same day versus over different days in primary open-angle glaucoma.

Methods.

Twenty-five eyes from 25 patients with primary open-angle glaucoma were submitted to a diurnal curve on the same day, 5 measurements, 2.5 hours apart, from 8:00 AM to 6:00 PM. For the measurements on different days, we randomly selected one time point from the diurnal curve for each patient. All patients were then instructed to return every 3–7 days to complete all 5 measurements. The maximum, minimum, and IOP fluctuation were compared between the 2 methods.

Results.

The IOP fluctuation (maximum-minimum) was similar when we measured the IOP on different days (5.0±2.6 mmHg vs 4.0±1.2 mmHg, p=0.08). There was no difference regarding the minimum or maximum IOP assessed in the diurnal curve or over different days. There was a high correlation for the maximum IOP (r=0.863, p<0.001) and the minimum IOP (r=0.708, p<0.001) by either method of measuring during the same day or different days, as well as for all measurements (8:00 AM: r=0.718, p<0.001; 10:30 AM: r=0.479, p=0.01; 1:00 PM: r=0.628, p=0.001; 3:30 PM: r=0.757, p<0.001; and 6:00 PM: r=0.910, p<0.001).

Conclusions.

IOP fluctuation in primary open-angle glaucoma can be assessed using IOP measures on different days, at different time points, which strongly correlate to a diurnal curve.