OBJECTIVE: To compare pulsatile ocular blood flow (POBF) and intraocular pressure (IOP) in primary open angle glaucoma (POAG) and normal control group matched for age, sex and refraction error, to investigate the rule of hem-dynamics in POAG and to determine the sensitivity and specificity of POBF measurement as a diagnostic test for glaucoma. METHODS: Prior to the test a questionnaire was completed to determine age, sex, refractive error, family history of glaucoma, history of eye diseases, ocular medication, medical history and using of systemic beta-blockers. Patients of POAG were determined by following diagnostics standards: (1) Three IOP >25 mm Hg in different times of one day. (2) The fluctuate of IOP > 8 mm Hg during 24 hours. (3) Typical glaucoma changes in the visual field. (4) Typical glaucoma changes in optic disc. There were 100 POAG subjects with single eye observed (50 male and 50 female). We picked up 100 eyes randomly (50 male and 50 female) in 534 normal persons who matched for following conditions: (1) Sex. (2) Discrepancy of age less than 5 years. (3) Discrepancy of the refraction error less than +/- 2.00 DS. as the normal comparison group. The tonometer used was the POBF Tonometry. Pulse amplitude of IOP (PA), pulsatile ocular blood flow (POBF), pulse/heart rate (PR), maximum-IOP (max-IOP), minimum-IOP (min-IOP) and average IOP (aver-IOP) were obtained before the medical therapy and 1 or 2 weeks after the operation. The correlation between the POBF & mean value of the perimeter was analyzed. POBF was analyzed to determine the sensitivity and specificity of POBF measurement as a diagnostic test. RESULTS: The value of POBF in POAG and normal control was (9.72 +/- 3.47) microl/s and (12.04 +/- 4.68) microl/s, respectively. POAG patients' POBF, PV, PA, and AVE-IOP were less than those in the normal control, and the difference was statistically significant. There was no statistically significant correlation between the changes of visual field and POBF (r = 0.224, P = 0.219). The sensitivity and specificity of using the POBF for diagnosis of POAG (less than 10.75 microl/s being abnormal) were 0.422 and 0.623, respectively. CONCLUSION: Abnormal of vas-autoregulation and blood supply play a role in the pathogenesis of POA. Due to the lower sensitivity and specificity, it is not suitable to use POBF as a diagnostic test to distinguish the POAG and normal. But the POBF reflects the change of blood flow in a pulsing cycle and provide more information than the measurement of IOP only.