Vision-related quality of life in non-neovascular age-related macular degeneration: a protocol for systematic review and meta-analysis

Age-related macular degeneration (AMD) is a progressive retinal disease and a major cause of visual impairment in older adults. Non-neovascular AMD (non-nAMD), the more common phenotype, can substantially impair vision-related quality of life (QoL) even when visual acuity remains relatively preserved. The 25-item National Eye Institute Visual Function Questionnaire (NEI-VFQ-25) is the most widely used instrument for assessing vision-related QoL in AMD. However, QoL in non-nAMD has not been systematically synthesised across disease stages and settings. This review aims to summarise vision-related QoL in treatment-naive patients with non-nAMD, examine how QoL varies by disease stage and measurement instrument and identify study-level factors associated with QoL differences. We will search MEDLINE, Embase, EBM Reviews and APA PsycINFO from inception for original studies reporting mean values or mean differences, with corresponding variability, for overall or subscale scores from the NEI-VFQ-25 or other validated vision-related QoL instruments. Two reviewers will independently screen studies, extract data and assess risk of bias using the appropriate Joanna Briggs Institute critical appraisal checklist for analytical cross-sectional studies. Random-effects meta-analyses will be conducted to pool NEI-VFQ-25 composite and subscale scores by non-nAMD stage and, where available, to estimate differences between stages or versus controls. Instrument-specific meta-analyses will be performed for other QoL measures when feasible and standardised metrics will be used to combine instruments assessing similar constructs but using different scales. Meta-regression will explore whether QoL varies with study-level characteristics. The findings will clarify the functional burden of non-nAMD and support future clinical research and trial design.