The association between myopia and primary open-angle glaucoma: A systematic review and meta-analysis.

Author: Wu J, Hao J, Du Y, Cao K, Lin C, Sun R, Xie Y, Wang N.

Geographical coverage: India, China, Korea, Sri Lanka, Australia, America, Singapore and Japan.

Sector: Biomedical

Sub–sector: Risk

Equity focus:  Not reported

Study population: Patients with primary open-angle glaucoma

Review type: Epidemiology (risk association) review

Quantitative synthesis method: Meta-analysis

Qualitative synthesis method: Not applicable

Background

Myopia is one of the most common eye disorders and a leading cause of global visual impairment. Its relationship with primary open‑angle glaucoma (POAG) remains unclear, with recent studies reporting positive, negative or neutral associations.

Objectives 

To clarify the association between myopia and POAG and to explore how myopia severity influences POAG risk and progression.

Main findings

Myopia increases the likelihood of developing POAG but may confer a modest protective effect against disease progression.

Twenty‑three studies were included: 16 cross‑sectional studies (69 249 participants) and seven cohort studies (1 687 participants). Pooled odds ratios (ORs) from cross‑sectional studies showed that myopia significantly raised POAG risk (OR 2.26, 95 % confidence interval [CI] 1.77–2.89; P < 0.001). The association strengthened with increasing myopia severity: low (OR 1.63, 95 % CI 1.35–1.96), moderate (OR 2.27, 95 % CI 1.38–3.73) and high (OR 3.47, 95 % CI 2.48–4.85). In contrast, pooled data from cohort studies suggested that myopia might slightly reduce the risk of POAG progression (OR 0.85, 95 % CI 0.73–0.99; P = 0.042).

Methodology

MEDLINE, Embase and Scopus were searched for English‑language studies published between 1 January 1970 and 31 October 2020 that assessed the association between myopia and POAG in adults. Three reviewers independently carried out searching, screening and data extraction. Random‑effects meta‑analysis generated pooled estimates; statistical heterogeneity was evaluated with the I² statistic, and publication bias with Egger’s test.

Applicability / external validity

The review did not explicitly discuss applicability. Evidence about the impact of differing myopia levels on POAG progression is limited, and further studies are warranted.

Geographic focus

The included studies were conducted in India, China, Korea, Sri Lanka, Australia, United States of America, Singapore, and Japan.

Summary of quality assessment

Confidence in the conclusions is low. The authors did not provide a list of excluded studies, specify the risk‑of‑bias tool or state how many reviewers extracted data.