Authors:Xiaotang Wang, Runsheng Wang, Ying Wang

Author Disclosure Block: X. Wang: None. R. Wang: None. Y. Wang: None.

Abstract Body:

Purpose: To assess the accuracy of different formulas for measuring 24-hour ocular perfusion pressure (OPP) and the applied value for the diagnosis and treatment of ischemic ocular fundus diseases. To compare the relations between different calculative formulas and ischemic ocular fundus diseases.

Study Design: Retrospective study

Methods: 361 patients (381 eyes) with ischemic ocular fundus diseases from July 2010 to December 2016 in our hospital were retrospectively analyzed. Patients were diagnosed by Optic nerve thickness analysis, visual field examination, visual electrophysiology, and Fundus fluorescence angiography. The 24-hour intraocular pressure (IOP) in the sitting position of all the patients was measured through non-contact tonometer. The systolic blood pressure (SBP) and diastolic blood pressure (DBP) of the brachial artery and heart rate were measured by electrocardiogram monitor simultaneously. As we know, the mean artery pressure (MAP) equals DBP+1/3(SBP-DBP). OPP can be calculated by four formulas: OPP A =(45%DBP-IOP), OPP B = 2/3MAP-IOP, OPP C = 95/140MAP-IOP, OPP D = MAP-IOP. The alarming value of OPP for ischemic ocular fundus disease is 10mmHg. OPP less than 10mmHg was regarded as hypoperfusion.

Results: 241 patients (67%) had more than twice the time-point of hypoperfusion. The onset of ischemic ocular fundus diseases in 236 patients (62%) was in accord with the time-point of hypoperfusion. Improvement of OPP and ocular hemodynamics was observed in 231 patients (64%) after treatment. Mean OPP by formula A, B, C and D were(32.63±7.04) mmHg, (49. 40±10.53) mmHg, (43.49±10.71) mmHg and (71.86±13.80) mmHg, respectively. The OPPcalculated by different formulas was statistically significant (F=23.508,P=0.000). There was a significant difference between formula A and D (t=-8.009,P=0.000). There was no significantly difference between formula B and C(t=1.244,P=0.229). OPP calculated by formula A is closest to the alarming value of 10mmHg and is the most credible method to measure OPP. The ranking of formulas by the closeness degree was A>C>B>D.

Conclusions: 24-hour OPP reflected the situation of IOP, blood Pressure, and retinal hemodynamics, providing the evidence of the diagnosis and treatment of ischemic ocular fundus diseases. Though the OPP obtained from these methods are all higher than the alarming value of 10mmHg, the OPP obtained through formula A are closest to the alerting value in accord with the ischemic ocular fundus diseases. We suggest that formula A is the optimal calculate for OPP.