Association Between Cardiovascular Disease and Cataracts: Protocol for a Systematic Review and Meta-Analysis

There is emerging evidence suggesting shared pathophysiological mechanisms between cataracts and cardiovascular disease (CVD), indicating a potential link between these 2 prevalent noncommunicable diseases. Oxidative stress, resulting from an imbalance between reactive oxygen species production and the body's antioxidant defenses, contributes to lens protein aggregation in cataracts and lipid oxidation in atherosclerosis, a key feature of several CVD subtypes. This shared pathophysiology implies that systemic vascular health may influence cataractogenesis. However, the epidemiological evidence supporting this relationship remains inconclusive.

The main objective of this systematic review is to synthesize existing evidence on the odds or risk of developing cataracts in adults with underlying CVD.

This systematic review will adhere to the PRISMA-P (Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols). Using the population, exposure, comparator, and outcome framework, this review will identify the association between established CVD and the risk of cataract development or needing cataract surgery. Systematic literature searches will be conducted in PubMed, Scopus, Web of Science, and Embase using MeSH terms from database inception to December 31, 2024. Original research articles involving adults (aged ≥18 years) that assess the statistical relationship between CVD and cataracts will be included. Two independent reviewers will screen studies, extract data, and appraise the studies' quality using the Newcastle-Ottawa Scale. If deemed feasible, meta-analyses will be conducted using random-effects models to calculate pooled effect estimates, with heterogeneity assessed using the I² statistic.

This study did not receive any external funding. The literature search, study screening, and data extraction will be conducted in 2026, and data analysis will be performed accordingly. The findings are anticipated to be published in 2027.

This systematic review will provide a consolidated and up-to-date evaluation of the relationship between CVD and cataracts. The findings will highlight the potential importance of integrating cardiovascular risk assessment into routine ophthalmologic care. Continued refinement of study methodologies and standardization of outcome measures may be needed to address observed heterogeneity and strengthen future evidence, ultimately supporting more holistic management of patients with coexisting cardiovascular and ocular conditions.