Abstract
Purpose: Ocular perfusion pressure (OPP) regulates the flow of blood to the optic nerve and is determined by the interaction between intraocular pressure (IOP) and blood pressure (BP). Low OPP increases the incidence of primary open-angle glaucoma (POAG). The aim is to compare the diurnal (i.e. morning vs. afternoon) and postural (i.e. seated vs. supine) OPP in healthy individuals from different ethnicities aged between 18 and 30 years. Methodology: Averaged IOP and BP measurements were obtained with an ICare rebound tonometer and an automated sphygmomanometer, respectively. Measurements were taken in the morning and afternoon, in the supine and seated positions in healthy young adults: Africans ( n = 10), white people ( n = 10), mixed-race people ( n = 10) and Indians ( n = 10). Results: The whole sample ( N = 40) displayed a statistically significant reduction in postural and diurnal OPP both in the supine position and in the morning, respectively. A comparative analysis revealed that Africans displayed statistically significant reduction in OPP when compared to other ethnicities. Discussion: A change in posture to the supine position has a greater impact on the reduction of OPP when compared to diurnal changes. Africans displayed clinically significant reduction in OPP which may increase the incidence of POAG in this ethnicity at an early age. Conclusion: Our findings question whether OPP should be considered as a biomarker in the dark-skinned individuals. An evaluation of BP and IOP in the supine position is recommended for all patients to obtain more conclusive readings.
Highlights
Glaucoma has been identified as the second leading cause of blindness worldwide after cataracts.[1]
Ocular perfusion pressure (OPP) can further be formulated as systolic OPP (SOPP), which is the difference between the systolic blood pressure (BP) and IOP5, and diastolic OPP (DOPP), which is the difference between the diastolic BP and intraocular pressure (IOP)
The IOP and BP measurements were obtained in the morning and afternoon at different postural positions of supine and seated to calculate the Mean OPP (MOPP), DOPP and SOPP
Summary
Glaucoma has been identified as the second leading cause of blindness worldwide after cataracts.[1] Extensive research has suggested an association between vascular risk factors and glaucoma.[2,3,4] intraocular pressure (IOP) remains a significant risk factor for glaucoma, studies have noted that arterial blood pressure (BP) can influence the disease progression.[4,5] Ocular perfusion pressure (OPP) regulates the flow of blood to the optic nerve and is determined by the interplay between IOP and BP.[6] Considering the relationship between OPP and open-angle glaucoma (OAG) is multifaceted, the focus of this study was to compare the postural and diurnal aspects of OPP in healthy individuals of different ethnicities. The difference between the systolic and diastolic BP is factored by one-third and added to the diastolic BP to determine the MAP.[5]
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