Blood Pressure Dominates IOP in Effects on Ocular Perfusion Pressure

Abstract

Abstract: : Purpose: To assess the predominant factors involved (IOP and blood pressure) in causing a change in ocular perfusion pressure (PP).Methods: All procedures were approved by an IRB, and informed consent obtained.Blood pressure, heart rate, and IOP OU of fifteen normal subjects (twelve male and three female, with a mean age of 27.3 ± 8.9 years) were taken before and two hours after 60 mg PO nicergoline. Baseline and post-drug measurements were compared by paired Wilcoxin ranked sum test. Linear regression was used to compare percent change of each parameter with PP ( PP = 2/3 of mean arterial pressure - IOP). Results: There was no significant change in blood pressure or heart rate as compared to baseline measurements. IOP was significantly decreased (p = 0.003 OD and 0.019 OS) as compared to baseline measurements. The percent change in PP was significantly correlated with change in systolic blood pressure (p = 0.0002, r² = 0.736), diastolic blood pressure (p < 0.0001, r² = 0.857), and heart rate (p = 0.0229, r² = 0.388). There was no significant correlation with PP and IOP. Conclusion: Ocular perfusion pressure is calculated from blood pressure and IOP; however, changes in PP may not correlate with measured changes in IOP. Changes in systemic blood pressure may prove more important in bringing about changes in PP.

Keywords: intraocular pressure • blood supply