Abstract
Purpose:
Aim of the study was to evaluate the central retinal venous pulsation pressure (CRVPP) in intraocular pressure (IOP) controlled early, moderate and advanced open-angle glaucoma patients and a healthy control group.
Methods:
CRVPP was measured with a contact lens dynamometer, calibrated in mmHg (Meditron GmbH, Voelklingen, Germany) in 34 IOP-controlled open-angle glaucoma patients who were selected consecutively and according to the stage of their visual fields and in 27 healthy controls. Visual fields were tested with the Humphrey 30-2 SST program (Zeiss Humphrey Systems, Dublin, CA, USA). A mean deviation (MD) of more than -6dB was considered as early, between -6dB and -12dB as moderate and of less than -12dB as advanced visual field defect. The ocular perfusion pressure (OPP) in the retina and prelaminar region was conventionally calculated as OPP1=2/3MAP-IOP (MAP= systemic mean arterial blood pressure) and, using the measured CRVPP in the formula, as OPP2=2/3MAP-CRVPP. Statistical analysis was performed using the Kruskal-Wallis, the Mann-Whitney and the Wilcoxon test.
Results:
Median CRVPP was 12.0mmHg (IQR: 10.0-14.0) in controls, 14.0mmHg (IQR: 11.0-15.3) in early, 38.9mmHg (IQR: 29.9-48.4) in moderate and 34.6mmHg (IQR: 23.9-51.0) in advanced glaucoma cases. Controls and early glaucoma cases showed a statistically significant lower CRVPP compared to moderate and advanced cases (P=0.001). The conventionally calculated OPP1 was 49.8 mmHg (IQR 42.7-57.6) for controls, 58.7 mmHg (IQR 56.9-59.4) for early, 56.6 mmHg (IQR 51.2-64.4) for moderate and 59.3 mmHg (IQR 53.9-61.6) for advanced cases. OPP2 was 53.8 mmHg (IQR 45.7-62.1), 59.9 mmHg (IQR 54.4-62.0), 25.1 mmHg (IQR 15.7-38.6) and 34.2 mmHg (IQR 20.4-47.5) in these groups. This difference was statistically significant for controls (OPP2 higher; P=0.001), for moderate (OPP2 lower; P=0.003) and advanced (OPP2 lower; P=0.002) cases.
Conclusions:
In glaucoma CRVPP seems to be much higher than previously thought. A high CRVPP is associated with more advanced visual field defects and might further compromise the perfusion pressure in the prelaminar region of the optic nerve head. This might be of clinical importance especially in IOP-controlled more advanced cases and should be considered as a possible risk factor for progression.
Keywords: 436 blood supply •
629 optic nerve •
568 intraocular pressure