Effectiveness of intraocular pressure phasing

Abstract

Purpose: To investigate the value of intraocular pressure phasing during normal working hours in patients with and without anti‐glaucoma treatment. Methods: This study is a retrospective case note review of 61 patients referred for intraocular pressure phasing (every 2 hours from 8.00am to 4.00pm). Comparison between pre‐phasing intraocular pressure measurements (mean and range) taken during earlier routine visits (5 measurements) and phasing intraocular pressure (mean and range) for each eye was performed using paired t‐test. Scatter plots were used to display the relationship of pre‐phasing and phasing intraocular pressure. Subgroup analysis of 119 eyes into untreated and medically treated groups was performed. Results: Eyes in the untreated group (51 eyes) showed no difference between the mean intraocular pressure at pre‐phasing and phasing (p value=0.8) but a significant difference between the intraocular pressure range (p value=0.007). For the medically treated group (68 eyes), there was no significant difference between the mean intraocular pressure at pre‐phasing and phasing (p value=0.9) and no significant difference between the intraocular pressure range (p value=0.66). In the total 119 eyes the peak intraocular pressure was found to occur at 10‐11am. Conclusions: Intraocular pressure phasing is most useful on untreated patients. Intraocular pressure phasing is less likely to give much additional data, compared to pre‐phasing intraocular pressure measurements, in treated patients. If a clinician wanted to identify the peak intraocular pressure the best time is between 10‐11 am.