Accuracy and precision of visual acuity tests: A systematic review and meta-analysis across testing strategies

Visual acuity testing across 82 validation studies (10,873 participants) shows pooled mean bias of 0.01 logMAR, but substantial variability with intertest LoA half-width 0.19 logMAR and test-retest CoR 0.14 logMAR.

• Why it matters: Measurement variability may limit clinical utility as VA testing shifts from examiner-guided to examinee self-guided formats, yet accuracy and precision across strategies were not well synthesized.
• What they did: Following PRISMA, the authors meta-analyzed intertest and test-retest Bland-Altman mean bias, limits of agreement, and coefficient of repeatability from PubMed, Google Scholar, and Scopus (1983–02 Dec 2024), using multilevel random-effects models and QUADAS-2 risk-of-bias assessment.
• The result: Bias was minimal across strategies, while precision was worse in remote and unsupervised testing (intertest LoA half-width 0.27 vs 0.19 logMAR; 0.26 vs 0.19 logMAR), with marginal differences by optotype sampling and response input.

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