Distribution of Ocular Perfusion Pressure and its Relationship with Intraocular Pressure in Patients with Primary Open Angle Glaucoma in Enugu, South East, Nigeria

Background: Ocular perfusion pressure (OPP) has been suggested as a possible risk factor for the development and progression of primary open angle glaucoma (POAG). Aim: To determine the distribution of OPP and its relationship with intraocular pressure (IOP) in Nigerian patients with POAG. Patients and Methods: A descriptive and comparative survey was adopted. A total of 120 subjects, 60 newly diagnosed POAG and 60 non-glaucomatous (NG) subjects, aged 40 years and above, who attended the ophthalmic clinic of University of Nigeria Teaching Hospital Enugu were recruited over a six-month period in 2019. All the subjects had ocular examination, blood pressure and IOP measurements. Statistical package for social sciences software version 25 was used for data analysis. Chi-square test, independent samples t-test, and Mann-Whitney U test were used for comparison while Pearson correlation and simple linear regression were used to ascertain the relationship. A P value of <0.05 was considered significant. Result: The mean age of the participants was 57.9 + 11.9 years. The mean OPP was found to be significantly lower in the POAG subjects (Right eye, R = 43.6 +/- 12.6, Left eye, L = 41.9 +/- 13.3) mmHg compared with the NG group (R = 53.9 +/- 10.9, L = 53.7 +/- 10.9) mmHg (p < 0.001 for both eyes). A significant inverse relationship was observed between OPP and IOP in POAG subjects (p < 0.001), while there was none in NG subjects. Conclusion: OPP was lower in POAG subjects than in NG subjects. The observed relationship suggests that reduced OPP may play a role in the development of POAG.