Correlation between ocular perfusion pressure fluctuation and glaucoma severity

The aim of the study is to assess the correlation between ocular perfusion pressure (OPP) fluctuation and the severity of glaucoma. Forty-three patients with primary open-angle glaucoma (POAG) were enrolled in the study. All subjects had intraocular pressure (IOP) and blood pressure measured at three time points (7:00 a.m., 1:00 p.m. and 7:00 p.m.). OPP was calculated based upon blood pressure and IOP, and OPP fluctuation was calculated as the standard deviation of the three measurements. OPP fluctuation was correlated with a structural measure (cup-to-disk ratio) and two functional measures [mean deviation (MD) and pattern standard deviation (PSD) values from automated perimetry] with the Pearson's correlation coefficient. OPP fluctuation showed statistically significant correlation with both MD (r = -0.35, P = 0.01) and PDS (r = 0.44, P = 0.00). No correlation was found between OPP fluctuation and cup-to-disk ratio (r = 0.10, P = 0.48). POAG patients with higher OPP fluctuation have greater severity of disease as measured by functional parameters.