Abstract
Purpose: :
To compare the 24-hour IOP, blood pressure (BP), and perfusion pressure (PP) of primary open-angle glaucoma (POAG) patients and healthy individuals.
Methods: :
24 healthy individuals and 29 POAG patients were prospectively recruited. Exclusion criteria for both groups were: a) previous intraocular surgery or laser procedure; b) systemic hypertension, diabetes mellitus, or any other disease that may affect arterial BP; c) use of vasoactive medications that could influence BP measurements; d) presence of other ophthalmic diseases. Individuals were admitted at the Hospital and underwent IOP and BP measurements every 2 hours, starting at 8:00 AM until 6:00 AM of the next morning. IOP measurements were made by a masked observer with a Goldmann tonometer at the slit-lamp from 8:00 AM to 10:00 PM and with the Perkins tonometer, with the patient lying in a horizontal position, from 12:00AM to 6:00 AM. Systolic and diastolic BP (SDP and DBP) measurements were performed with an automated device, which remained on the right arm of the patient.
Results: :
Mean age, race and gender distributions did not differ significantly between the groups (P>0.05). Mean IOP measurements in POAG patients were significantly higher than those obtained in controls at all time intervals (P<0.001). Mean SBP was significantly higher in POAG patients from 4:00 AM to 10:00 AM, and also at 2:00PM and 6:00 PM (p<0.05). Mean DBP was significantly higher in POAG patients at 8:00 AM and 10:00 AM (p<0.01), but was significantly lower in POAG patients at 4:00 AM (p=0.025). Mean SPP was significantly higher in POAG patients at 8:00 AM and 10:00 AM (p<0.01). Mean DPP was significantly lower in POAG patients at night, from 12:00 AM to 6:00 AM (p<0.05).
Conclusions: :
POAG patients show a distinct diurnal behavior of PP. Although higher SPPs are observed in POAG patients during the morning, lower DPPs are found during the night.
Keywords: circadian rhythms • blood supply • intraocular pressure