Background To evaluate the central retinal venous pulsation pressure (CRVPP) in patients with intraocular pressure (IOP)-controlled early, moderate and advanced open-angle glaucoma and a healthy control group.
Methods CRVPP was measured with a contact lens dynamometer calibrated in mm Hg (Meditron GmbH, Voelklingen, Germany) in 34 patients with IOP-controlled open-angle glaucoma who were selected consecutively and according to the stage of their visual fields and 27 age-matched healthy controls. If a spontaneous venous pulsation was seen, CRVPP was considered to be equal to IOP. Visual fields were tested with the Humphrey 30-2 SST programme. The ocular perfusion pressure 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 and the Mann–Whitney U test.
Results Median CRVPP was 14.0 mm Hg (IQR 12.0–16.0) in controls, 15.0 mm Hg (IQR 14.0–17.0) in early, 38.9 mm Hg (IQR 29.9–48.4) in moderate and 34.6 mm Hg (IQR 23.9–51.0) in advanced glaucoma cases. The conventionally calculated OPP1 was 49.8 mm Hg (IQR 42.7–57.6) for controls, 56.9 mm Hg (IQR 55.3–58.8) for early, 56.6 mm Hg (IQR 51.2–64.4) for moderate and 59.3 mm Hg (IQR 53.9–61.6) for advanced cases. OPP2 was equal to OPP1 in the control group, 56.1 mm Hg (IQR 54.5–57.9) in early, 25.1 mm Hg (IQR 15.7–38.6) and 34.2 mm Hg (IQR 20.4–47.5) in moderate and advanced cases. This difference was statistically significant for moderate (OPP2 lower; p=0.003) and advanced (OPP2 lower; p=0.002) cases.
Conclusions In more advanced cases of glaucoma, CRVPP seems to be much higher than previously thought. This might further compromise the perfusion pressure in the prelaminar region of the optic nerve head and be of clinical importance, especially in IOP-controlled more advanced cases. This should be considered as a possible risk factor for progression.
Trial registration number ClinicalTrials.gov ID: NCT01503996.
- open-angle glaucoma
- central retinal venous pulsation pressure
- ocular perfusion pressure
- visual field