Relationship of systemic blood pressure with ocular perfusion pressure and intraocular pressure of glaucoma patients in telemedical home monitoring

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.