Measurement of ophthalmodynamometric pressure with the vented-gas forced-infusion system during pars plana vitrectomy.

PURPOSE To measure ophthalmodynamometric pressure (ODP) with the vented-gas forced-infusion (VGFI) system during vitrectomy in patients with various vitreoretinal disorders and to investigate factors related to ODP. METHODS This study included 169 eyes of 169 patients undergoing pars plana vitrectomy. After core vitrectomy, the intraocular pressure was gradually raised by using the VGFI system. When the central retinal artery or its branches on the optic nerve head showed pulsations, the pressure was recorded as ODP. Diastolic blood pressure (DBP) and systolic blood pressure (SBP) were measured simultaneously with ODP. Multiple regression analysis was performed to investigate the relationship between ODP and various explanatory variables: DBP, SBP, age, presence of diabetic mellitus (DM) and hypertension (HT), body mass index, and serum total cholesterol. RESULTS ODP was 66.9 +/- 12.5 mm Hg (range, 15.5-103.7), and it correlated significantly with DBP (r = 0.60, P < 0.0001) but not with SBP (r = 0.12, P = 0.12). ODP in DM patients who had proliferative diabetic retinopathy and diabetic macular edema was lower than that in non-DM patients, whereas DBP was not significantly different between the two groups. Similar results were obtained in HT patients. Multiple regression analysis revealed that ODP had a significant correlation with DBP (P < 0.0001), presence of DM (P = 0.02), and presence of HT (P = 0.03). CONCLUSIONS VGFI is a new method of determining ODP. ODP was significantly associated with DBP and was lower in patients with DM and HT.