Purpose: In a significant number of glaucoma patients, progression of visual field loss occurs despite adequate intraocular pressure (IOP) control. Other factors, mainly vascular, seem to play a role in the pathogenesis of these glaucomas. The purpose of this study was to investigate the role of blood pressure (BP) as one of the vascular risk factors for progression of glaucomatous damage.
Methods: Eighty-three glaucoma patients were categorizated as to whether their visual field defect were stable or progressive in the face of clinically stable IOP; all patients were followed for at least two years. The mean systolic and diastolic BP were determined, using a 24-hour ambulatory recording device, during diurnal (6 am-10 pm) and nocturnal (10 pm-6 am) periods. For each patient, the nocturnal systolic and diastolic dips, and the BP variability (i.e. standart deviation, and percentage decrease from maximal to minimal readings) were determined.
Results: Forty-three patients had stable visual fields (25 females, 58.9 years old +/- 6.88; 18 males, 58.6 years old +/- 11), while 40 patients showed progressive visual field loss (23 females, 67.4 years old +/- 9.98; 17 males, 64.5 years old +/- 9.44). In the progressive group, women were older (p = 0.017), systolic (p = 0.0375) and diastolic (p = 0.0083) dips were greater, as also BP variability: systolic standard deviation was greater (p = 0.027) as percentage decrease from maximal systolic readings (p = 0.034). There were no difference for systolic, diastolic, diurnal or nocturnal mean BP in these two groups.
Conclusions: The finding in this study suggests that age, decreased nocturnal BP and high BP variability may be additional risk factors for progression of glaucomatous field loss.