Four Measures of Intraocular Pressure Fluctuation: Which Correlates Most Optimally With Actual Office-hour Readings?

摘要

Purpose:To compare the power of the 4 intraocular pressure (IOP) measures, that is, peak, mean, range, and SD, over a 24-hour period in predicting IOP variations in order to determine which measure of IOP fluctuation correlates best with actual office-hour readings in glaucoma patients and healthy subjects.Methods:For this prospective study, 25 subjects with untreated primary open-angle glaucoma and 33 healthy individuals were hospitalized for 24 hours. Measurements of the subjects' IOP for both eyes were recorded with a Goldmann applanation tonometer every 3 hours in the sitting position during the daytime (9 am to 9 pm) and with a TonoPen in both the sitting and supine positions for 24 hours. Only 1 eye was selected randomly per subject for the final analysis. The strength of association between the estimated values and the actual 24-hour IOP data in habitual body positions was analyzed using the coefficient of determination (R-2). The differences were calculated. The percentage of subjects with estimated IOP values falling within the cutoff values from the 24-hour data were assessed.Results:The peak IOP was captured outside office hours in 57% of the young subjects, 75% in the elderly control group, and 52% of the glaucoma patients. The estimation of the strength of association for the mean IOP and peak IOP showed strong to moderate correlations (R-2 range from 0.29 to 0.95) compared with the estimation of range and SD of IOP fluctuation, which demonstrated weak to moderate relationships (R-2 range from 0.001 to 0.69). The percentage of significant cases mostly corresponded with the correlation.Conclusions:With the combination of sitting and supine position readings during office hours, the study provides promising results in estimating the mean and peak IOP in glaucoma patients and healthy subjects; however, it showed little advantage in range and SD of IOP fluctuation.