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A.P. Doan, M.B. Zimmerman, W. Alward, E. Greenlee, Y. Kwon; Diurnal Fluctuation and Concordance of Intraocular Pressure in Glaucoma Suspects and Ocular Hypertension Patients . Invest. Ophthalmol. Vis. Sci. 2005;46(13):4833.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: The one–eye drug trial for glaucoma medications reducing the intraocular pressure (IOP) assumes that the diurnal fluctuation of the IOP in both eyes is concordant. Our study objective was to determine the diurnal variation and concordance of IOP measured in glaucoma suspect (Suspect) and ocular hypertension (OHTN) patients. Methods: Amongst the 142 diurnal curves on record, charts were excluded from the study if there was evidence of: glaucoma, glaucoma surgery, trauma, use of anti–glaucoma drops, or an incomplete diurnal curve record. The remaining 83 diurnal curves (68 Suspect and 15 OHTN) were included in our analysis. The IOPs were measured using Goldmann applanation tonometry at 07:00, 10:00, 13:00, 16:00, 19:00, and 22:00. The diurnal curves were analyzed to determine if there was concordance in the diurnal fluctuation between the eyes. The average Pearson correlation coefficient (r) for the two patient groups was estimated to measure the linear association of IOP over the 6 time points between the two eyes within each subject. The correlation between the IOP OD and OS was first computed for each subject from each set of diurnal curves with the estimate of the average correlation calculated from the z–transform of these individual correlations. Results: The pooled mean IOP were 14.9 and 23.1 mmHg for Suspect and OHTN groups respectively. The average correlations between OD and OS IOP were 0.78 (95% CI: 0.71, 0.82) for Suspect, and 0.86 (95% CI: 0.77, 0.92) for OHTN. The standard deviation of the IOP between eyes within each subject was found to be similar for all the time points. This was at most 1.60 mmHg (95% CI: 1.37, 1.92) with a coefficient of variation (CV) of 10.76% for Suspect, and 2.63 mmHg (95% CI: 1.94, 4.07) with 10.06% CV for OHTN. Observed difference in IOP between eyes was less than 3.81 and 6.06 mmHg in 90% of Suspects and OHTN patients respectively. Conclusions: These findings indicate the IOP of both eyes change in the same direction (positive correlation) and with similar magnitude. We conclude the diurnal variations in IOP between eyes are largely concordant.
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