Meta-Analysis: A to Z for Healthcare Professionals.

Meta-analysis is a powerful tool in evidence-based medicine, allowing researchers to synthesize findings from multiple studies to enhance clinical decision-making. This technical report provides a step-by-step guide on conducting a meta-analysis using JASP (Jeffreys's Amazing Statistics Program, University of Amsterdam, Amsterdam, Netherlands), an open-source statistical software. Two case studies illustrate its application: (1) an analysis of the association between serum vitamin D levels and intraocular pressure in primary open-angle glaucoma (POAG) and (2) an evaluation of the relationship between cardiovascular mortality and open-angle glaucoma (OAG). The study follows PRISMA guidelines and employs a random-effects model to account for heterogeneity. Results indicate no significant association between vitamin D and POAG (p = 0.122), while the cardiovascular disease-glaucoma meta-analysis shows high heterogeneity (I² = 99.54%). These findings highlight the challenges of interpreting meta-analyses with variable datasets. This report serves as a practical resource for researchers and clinicians, providing essential tools to conduct meta-analyses effectively and apply them in healthcare research.