A New Strategy for Diurnal Intraocular Pressure Curve

Abstract

Purpose. To investigate whether there is agreement between intraocular pressure (IOP) readings in the supine position at 6 am upon awaking (before getting out of bed) and the IOP at 8 am, also measured in supine position after remaining 30 minutes in this position. Methods. In a sample of 50 eyes of 50 patients (normal, glaucoma suspect, and glaucoma patients), 6 am IOP was measured in the supine position upon awaking and before getting up, while 8 am IOP was measured on the same day, also in the supine position after 30 minutes in this position. Results. The IOP values at 6 am were mean 16.06±3 mmHg; median 15.5 mmHg (range 10-25.5 mmHg). For the 8 am readings, the average was 15.94±4 mmHg and the median 15 mmHg (range 10-25.5 mmHg). The difference between mean 6 and 8 am IOPs was 0.13±0.9 mmHg (confidence interval −0.14 to 0.40). Pearson correlation coefficient between the 6 and 8 am IOPs for the total sample was r=0.97 (p<0.05). There were no significant differences in behavior regarding eyes with high IOP as compared to normal IOP eyes (repeated-measure analysis of variance, p=0.72). Conclusions. The 8 am IOP readings obtained in the supine position and under the conditions described were equivalent to 6 am IOP readings (as the first measure of the diurnal pressure curve [DPC]). This new strategy for DPC will make it a widely used tool in daily practice since it spares the need for hospitalization or home measurements.