Ocular Perfusion Pressure and Pulsatile Ocular Blood Flow in Normal and Systemic Hypertensive Patients.

Purpose: The purpose was to compare the ocular perfusion pressure (OPP) and the pulsatile ocular blood flow (POBF) in normal and systemic hypertensive patients. Materials and Methods: Totally, 121 individuals (normal n = 60, systemic hypertension patients n = 61) were enrolled in this prospective age-matched comparative study. Intraocular pressure (IOP) and systemic arterial pressure were measured in seated position with 2 min interval between the measurements using Goldmann applanation tonometer (GAT) and tycos sphygmomanometer, respectively. The OPP was calculated as 2/3 of mean arterial pressure (MAP) minus IOP. After 5 min in the seated position POBF measurements were taken with the ocular blood flow (OBF) tonograph. Results: Mean age was 57.5 years (range 35-72 years) in the normal group and 59.6 years (range 36-78 years) in the hypertensive group; majority of the patients were female (68.5% and 71% respectively in each group). Measured parameters in both the groups showed, systolic blood pressure (BP) (143.6 ± 20.5 mmHg vs. 121.9 ± 17.5 mmHg), diastolic BP (90.7 ± 13.5 mmHg vs. 80.1 ± 9.9 mmHg), MAP (108.4 ± 14.2 mmHg vs. 94.2 ± 11.2 mmHg), and OPP (57.6 ± 14.6 vs. 48.7 ± 10.6 mmHg) were significantly greater (P = 0.001) in systemic hypertensive patients in comparison to normals. However, there was no difference in OBF tonograph values in both groups. The IOP measured by the OBF tonograph was higher than GAT in both groups, but the difference was not statistically significant (P = 0.41). Conclusion: Systemic hypertensive patients have a higher OPP in comparison to normal patients, but they do not have higher POBF. More studies are required to evaluate the role of the OPP in different ocular pathologies affecting the POBF.

Pulsatile Ocular Blood Flow in Healthy Koreans

PURPOSE: To determine the normal reference range of pulsatile ocular blood flow (POBF) values in healthy Korean subjects and to find out the factors that may affect them. METHODS: A total of 280 eyes of 280 normal subjects were included in this study. Best corrected visual acuity (BCVA), intraocular pressure (IOP), axial length, POBF, systemic blood pressure, and pulse rate were measured. The mean, standard deviation, range, and the 5th and 95th percentiles of POBF were calculated, and the influences of various parameters to POBF were determined by multiple regression analyses. RESULTS: The mean POBF value was 766.0+/-221.6 microliter/min in men and 1021.1+/-249.5 microliter/min in women. The 5th and 95th percentiles for POBF values were 486.0 microliter/min and 1140.0 microliter/min in men and 672.0 microliter/min and 1458.0 microliter/min in women. The POBF values were significantly influenced by gender, mean blood pressure, pulse rate, and axial length. CONCLUSIONS: Even though the POBF values were influenced by gender, BP, and axial length, we could define the normal reference range of POBF in healthy Koreans.

Pulsatile Ocular Blood Flow Measurements in Ocular Trauma Patients

The objective of this study was to ascertain the elationship between the various ocular traumas and the change of pulsatile ocular blood flow[POBF] measured with Ocular Blood Flow Tonograph[OBF Laboratories, UK Ltd.]. We tested POBF with Ocular Blood Flow Tonograph 3 times repeatedly within 48 hours after trauma in the 33 ocular trauma patients.In all the trauma eyes, heart rate[HR]and intraocular pressure[IOP]were higher and pulse amplitude [PA], pulse volume[PV], POBF were lower than in all the fellow eyes.In the hyphema group, HR, IOP, PA, PV, POBF were higher, especially IOP and OBF%S.D.were statically significant, than in non-hyphema group.In the orbital fracture group, only POBF and OBF%S.D.were higher than those of in non-fracture group. Therefore, these results show the change of POBF after various ocularinjuries in the ocular trauma patients.The further studies to follow up the serial change of POBF are necessary.

Reproducibility of Pulsatile Ocular Blood Flow Measurement by OBF Tonograph

To evaluate the reproducibility of pulsatile ocular blood flow(POBF), bilateral POBFs of 10 volunteers were measured 3 times serially by OBF tonograph system(OBF laboratories, UK Ltd.). The POBFs were recorded in sitting position using pneumotonometer attached at slit lamp. After measurement of POBF, intraoculat pressure(IOP) was measured by Goldmann applanation tonometry. Mean values of pulse amplitude(PA), pulse volume(PV), POBF, IOP were 2.0+/-0.4mmHg, 5.1+/-1.5microliter, 701+/-197microliter/min, 13.9+/-2.5mmHg, respectively. Average of standard deviation of POBF was 7.0+/-1.9%. Mean value of IOP using Goldmann applanation tonometry was 12.8+/-2.6mmHg. Coefficient of reliability of the repeated measurement of POBF was 83%, analyzed by intraclass correlation. Coefficient of variation of the repeated measurement of POBF was 5.2%. Linear regression analysis of the Goldmann applanation tonometer on the measurements of IOP witn the tonograph showed a regression coefficient of 0.91. In conclusion, reproducibility of POBF measurement by OBF tonograph was acceptable and compatible with conventional technique. Further studies are required to measure the POBF in glaucoma patients.

The Effect of Oral Calcium Channel Blockers on the Ocular Blood Flow

Pulsatile ocular blood flow(POBF) System can measure the ocular blood flow easily and reliably. We attempted to investigate if oral calcium-channel blockers such as nifedipine and verapamil used for treatment of normal tension glaucoma increase the ocular blood flow in normal eyes by using above instrument. Twelve normal volunteers who have no ocular and systemic disorder history were involved in this study, and their ocular blood flow, intraocular pressure, systolic and diastolic blood pressure and pulse rate were measured. We performed the same study for 14 normal volunteers using verapamil. Systolic and diastolic blood pressures were decreased significantly after administration of calcium-channel blockers(P0.05). The intraocular pressure did not vary after administration of verapamil, but elevated in mean by 1.1mmHg after administration of nifedipine(P<0.05). Our study showed oral calcium-channel blockers, nifedipine and verapamil, did not increase the ocular blood flow in normal subjects with use of POBF.