Ocular Perfusion Pressure and the Risk of Open-Angle Glaucoma: Systematic Review and Meta-analysis

Abstract

Low ocular perfusion pressure (opp) has been proposed as an important risk factor for glaucoma development and progression, but controversy still exists between studies. therefore, we conducted a systematic review and meta-analysis to analyze the association between opp and open-angle glaucoma (OAG). Studies were identified by searching PubMed and EMBASE databases. The pooled absolute and standardised mean difference in OPP between OAG patients and controls were evaluated using the random-effects model. Meta-regression analysis was conducted to investigate the factors associated with OPP difference between OAG patients and controls. A total of 43 studies were identified including 3,009 OAG patients, 369 patients with ocular hypertension, and 29,502 controls. The pooled absolute mean difference in OPP between OAG patients and controls was −2.52 mmHg (95% CI −4.06 to −0.98), meaning significantly lower OPP in OAG patients (P = 0.001). Subgroup analyses showed that oAG patients with baseline iop > 21 mmHg (P = 0.019) and ocular hypertension patients also had significantly lower OPP than controls (P < 0.001), but such difference in OPP was not significant between oAG patients with baseline iop of ≤21 mmHg and controls (P = 0.996). In conclusion, although no causal relationship was proven in the present study, our findings suggest that in patients with high baseline iop, who already have a higher risk of glaucoma, low opp might be another risk factor. Glaucoma, the second worldwide leading cause of blindness 1 , is a progressive and chronic disease characterized by the degeneration of retinal ganglion cell and its axon with corresponding visual field defect 2. Although therapeutic risk factors for preventing development and progression of glaucoma have been under wide investigation, lowering intraocular pressure (IOP) currently is the only effective treatment 3-5. Ocular perfusion pressure (OPP), the pressure to drive blood throughout the intraocular vasculature, with the degree of perfusion being influenced by the flow resistance, represents the blood flow and oxygen supplying the optic nerve head (ONH) 6,7. Thus, it has long been proposed that a decrease in OPP may increase the vulnerability of optic disc, leading to an increased risk of glaucoma development or progression 8-12. However, the association between OPP level and the risk of glaucoma has been debatable between studies. Some studies reported a significant association between low OPP and an increased risk of glaucoma 8-12. In contrast, others have reported the statistically non-significant or limited impact of OPP on the risk of glaucoma 13,14. Another hindrance when referring to OPP in clinic is that as various levels of OPP have been reported depending on the study design, glaucoma type, and patient characteristics (e.g. presence of hypertension, use of anti-hypertensive medication), this has led to controversy over the significant difference in the level of OPP between glaucoma patients and controls. In light of these, we performed a systematic review a...

Progression of functional and structural glaucomatous damage in relation to diurnal and nocturnal dips in mean arterial pressure

“…Such fluctuations also relate to changes in the ocular perfusion pressure in POAG ( 31 ), however, MAP variability can also affect the ocular perfusion pressure ( 7 ). Taking our findings into perspective, diurnal peaks in the intraocular pressure combined with diurnal MAP dips would likely result in repetitive drops in the ocular perfusion pressure ( 2 ), leading to glaucoma damage progression. On the other hand, as similarly reported in our study, glaucoma also relates to nocturnal hypotension ( 4 – 6 ).…”

“…Open-angle glaucoma (OAG) is a progressive optic neuropathy characterized by loss of retinal ganglion cells and visual deterioration in eyes with or without high intraocular pressure (1). The pathogenesis of OAG is unclear but recent evidence focuses on risk factors that affect the ocular perfusion pressure (2,3), with nocturnal hypotension being the most important systemic vascular risk factor (4)(5)(6). The most plausible hypothesis is that low mean arterial pressure (MAP) leads to reduced ocular perfusion pressure, promoting the loss of retinal ganglion cell death due to ischemia of the optic nerve head (7,8).…”

Nonocular Influencing Factors for Primary Glaucoma: An Umbrella Review of Meta-Analysis

“…Finally, 44 full-text articles were reviewed for further assessment. Seventeen articles were excluded for various reasons, including not being the largest MA investigating a risk factor ( n = 10) [25-34], full text could not be retrieved ( n = 2) [35, 36], full text was not in English ( n = 1) [37], full text was about IOP not glaucoma ( n = 5) [38-42], and not being an MA ( n = 4) [43-46]. Finally, 22 full-text articles [40, 47-67] were reviewed for further assessment summarized in Table 1.…”

“…Moreover, nicotinamide supplementation can improve inner retinal function in glaucoma patients [99]. About the influencing factors of the ocular, a study shows that low ocular perfusion pressure increases the risk of glaucoma [42].…”

Vascular Aspects in Glaucoma: From Pathogenesis to Therapeutic Approaches

“…A recent meta-analysis found a consistent association of low perfusion pressure and POAG but not NTG [ 11 ], even though some large epidemiologic studies were excluded due to mode of data reporting. The Leuven Eye Study found higher mean OPP values in glaucoma patients in a cross-sectional design [ 12 ].…”