The relevance of arterial blood pressure in the management of glaucoma progression: a systematic review

Author: Van Eijgen J, Melgarejo JD, Van Laeken J, Van der Pluijm C, Matheussen H, Verhaegen M, Van Keer K, Maestre GE, Al-Aswad LA, Vanassche T, Zhang ZY, Stalmans I.

Geographical coverage: The Netherlands, Australia, China, Romania, Korea, Nepal, Colombia, India, Pakistan,United States (US), Europe (unspecified).

Sector: Glaucoma

Sub-sector: Treatment

Equity focus: Not explicitly stated

Study population: Patients with glaucoma

Review type: Effectiveness review

Quantitative synthesis method: Narrative synthesis

Qualitative synthesis method: Not applicable

Background

Glaucoma is a leading cause of global blindness, expected to rise with an aging population. It involves progressive optic nerve damage, with intraocular pressure (intraocular pressure (IOP)) as the primary modifiable risk factor. However, vascular factors like arterial blood pressure (blood pressure (BP)) and ocular perfusion pressure (ocular perfusion pressure (OPP)) also play critical roles. Both hypertension and hypotension have been linked to glaucoma, with nocturnal hypotension and BP fluctuations strongly associated with disease progression. Despite evidence connecting BP dysregulation to optic nerve damage, guidelines for managing BP in glaucoma patients remain unclear.

Objectives

To provide clinicians with the latest literature regarding the management of arterial BP in glaucoma patients.

Main findings

The study found a significant correlation between systemic blood pressure (BP) levels and glaucomatous damage, underscoring the necessity for future clinical trials to refine management strategies and evaluate the long-term impact of BP control on glaucoma outcomes. Through a review of 80 studies, the authors identified that there is a bimodal relationship between BP and glaucoma, with both high and low BP contributing to an increased risk of the disease.

Hypertension was found to elevate intraocular pressure (IOP) due to increased production of aqueous humour and decreased outflow. Specifically, a 10 mmHg rise in BP results in an approximate 0.28 mmHg increase in IOP. While the majority of studies, including a meta-analysis conducted in 2020, established hypertension as a significant risk factor for the development and progression of glaucoma, some studies did not find a statistically significant impact of hypertension on glaucoma progression.

Patients with chronic hypertension, particularly those with poorly managed BP, tend to experience more severe glaucoma symptoms, including thinner retinal nerve fibre layers and more pronounced visual field defects. Nocturnal BP dipping, which is the normal decrease in BP during nighttime, was linked to glaucoma progression, especially when this dip was excessive, exceeding 10% or 20%.

Research indicated that individuals with abnormal nocturnal dipping are at a heightened risk of developing target-organ damage, including harm to the optic nerve head. Extreme nocturnal dipping can lead to decreased ocular perfusion pressure (OPP), thereby increasing the risk of ischemia in the optic nerve head and advancing glaucoma progression. Furthermore, the review noted that while some studies suggested antihypertensive medication might affect glaucoma risk, the findings were inconsistent.

The overarching conclusion from the review is clear: systemic BP management is intricately tied to glaucomatous damage, highlighting the urgent need for targeted clinical trials to develop more precise and effective BP management strategies for glaucoma patients.

Methodology

The authors conducted review that included articles assessing the association between arterial blood pressure (BP) and glaucoma. They specifically focused on studies evaluating BP in glaucoma patients, its impact on intraocular pressure (IOP), and various disease progression markers such as changes in the retinal nerve fibre layer, ganglion cell layer, visual field defects, and optic disc haemorrhages. Additionally, the review examined the effects of antihypertensive medication on glaucoma progression.

The search was performed using the MEDLINE, Embase, Web of Science, and Cochrane Library databases, with the last search conducted on 28 July 2022. The search criteria were limited to full-text articles published in English from 2015 to 2022. Relevant articles found by scanning the reference lists of included articles but published before 2015 were included only if they were cited in multiple included articles.

The review did not specify the screening process or the number of reviewers who independently assessed the articles. Similarly, it did not indicate whether the risk of bias was evaluated.

The number of reviewers who independently extracted the data was not specified, and the findings were synthesised narratively.

Applicability/external validity

The review examined the applicability and external validity of its findings, highlighting that the included studies exhibited variations in population demographics, study designs, and methods of BP measurement, which may limit their generalisability. Furthermore, differences in antihypertensive treatment protocols and BP monitoring techniques could affect the consistency of the results. The review underscored the necessity for large, multicenter trials with standardized methodologies to enhance the external validity of its conclusions.

Geographic focus

Included studies were conducted in The Netherlands, Australia, China, Romania, Korea, Nepal, Colombia, India, Pakistan, US, Europe (unspecified)

Summary of quality assessment

The review included only English studies. It did not assess bias risk or state the number of reviewers for screening and data extraction. Investigators were not contacted, and no list of excluded studies was provided. The Preferred Reporting Items for Systematic Reviews and Meta‑Analyses (PRISMA) diagram showed discrepancies in the number of included studies.