Relationship between optical perfusion pressure and systemic blood pressure on glaucoma: Case–control study

AIM: To investigate the relationship between blood pressure (BP), ocular perfusion pressure (OPP), intraocular pressure (IOP) and open angle glaucoma (OAG) in Primary Open Angle Glaucoma (POAG) patients and normal population. DESIGN: Cross-sectional observation study. MATERIALS AND METHODS: Hospital-based, case control cross-sectional study conducted on 150 patients, of which 75 people were included in the control group and 75 people in the glaucoma group. The diagnosis of cases was based on disc evaluation, gonioscopy, perimetry and applanation tonometry. Systolic and diastolic blood pressure (SBP and DBP) was measured with a Mercury Sphygmomanometer. Mean ocular perfusion pressure (MOPP) = ⅔ (mean arterial pressure − IOP), where mean arterial pressure (MAP) = DBP + ⅓ (SBP − DBP), systolic perfusion pressure (SPP) = SBP – IOP and diastolic perfusion pressure (DPP) = DBP − IOP was calculated. RESULTS: DBP, OPP, SPP and DPP showed positive association with POAG. There is positive correlation between IOP and SBP, DBP and there is a negative correlation between IOP, OPP, SPP and DPP. Lower OPP was strongly associated with an increased risk for POAG, with a relative risk of 6.27 and the odds ratio of 0.075 for those with OPP less than 50 mmHg. Similarly, a low DPP less than 55 mmHg were also associated with increased risk for POAG with relative risk of 5.3 and the odds ratio of 0.020. CONCLUSION: Low MOPP and low DPP show strong association with increased prevalence of POAG and are independent risk factors for OAG.