Background:    We evaluated the relation of systemic blood pressure with intraday variations in ocular perfusion pressure and intraocular pressure in patients with primary open-angle glaucoma in a telemedical home monitoring scenario.
    Material/Methods:    In the project Teletonometry Mecklenburg-Vorpommern (TTMV) patients were equipped with a home monitoring system for 24-hour self-measurements of intraocular pressure and blood pressure for a period of six months. All measurements were transmitted via telephone modem to an electronic patient record. Ocular perfusion pressure (OPP) was automatically calculated from self-measurements of intraocular pressure (IOP), systolic (SBP) and diastolic blood pressure (DBP) using the equation: OPP=[2/3*(2/3*DBP+1/3*SBP)]–IOP. We present the temporal characteristics of 70 patients with primary open-angle glaucoma based on 3282 self-measurements.
    Results:    The diurnal ocular perfusion pressure trend showed four characteristic phases (7am – 12am, 12am – 6pm, 6pm – 10pm, and 10pm – 7am). Between 7am and 12am ocular perfusion pressure and simultaneously systolic and diastolic blood pressure were significantly depressed compared to all other phases (p<0.05) whereas intraocular pressure showed no significant shifting. Instead intraocular pressure was significantly depressed between 6pm and 10pm (p<0.05) where ocular perfusion pressure reached the highest intraday values.
    Conclusions:    We found that ocular perfusion pressure in patients with primary open-angle glaucoma showed remarkable circadian fluctuations. A significant decrease in the morning was associated with significantly depressed systolic and diastolic blood pressure levels. In addition we observed normal intraocular pressure values in the morning but a significant decrease in the evening which did not affect ocular perfusion pressure. These conclusions strengthen the evidence that systemic blood pressure fundamentally influences ocular circulation and consequently glaucoma progression.

Keywords: Monitoring, Physiologic - methods, Intraocular Pressure - physiology, Hypertension - physiopathology, Glaucoma, Open-Angle - physiopathology, Glaucoma - physiopathology, Eye - physiopathology, Diastole - physiology, Circadian Rhythm - physiology, Blood Pressure - physiology, Perfusion, Systole - physiology, Telemedicine - methods