Development and preliminary psychometric evaluation of a spectacle trial-wear questionnaire for distance single-vision prescriptions

Background Existing vision questionnaires were not designed to standardize immediate patient appraisal of a distance single-vision spectacle prescription during trial wear. This study developed and preliminarily evaluated the Adult Spectacle Trial-Wearing Experience Scale (ASTWES) for this decision point. Methods Candidate items were informed by a structured literature search and interviews with eye-care and dispensing professionals, refined through two Delphi rounds, cognitively debriefed with 10 target patients, and piloted in 150 adults. Item reduction used corrected item-total correlations and principal-axis factoring with promax rotation. The independent formal psychometric evaluation sample comprised 393 adults within the prespecified 18–35-year age range; ordinal confirmatory factor analysis (CFA), robust maximum-likelihood sensitivity analysis, and reliability coefficients were used. An eligible subsample of 98 participants provided a 1-month satisfaction rating for exploratory association analyses. Results The final questionnaire contained 9 items in 3 correlated domains: clarity and focus, comfort and stability, and environmental adaptation. Retained pilot-item loadings ranged from 0.694 to 0.890. The correlated three-factor model was supported under both CFA estimators, whereas a single-factor model fit poorly. Subscale Cronbach's alpha values ranged from 0.769 to 0.803. Omega hierarchical was 0.641, favoring subscale-first interpretation. The overall mean item score correlated with 1-month satisfaction (Spearman rho = 0.753, p < 0.001); its exploratory AUC was 0.850 (bootstrap 95% CI 0.772–0.918). Conclusions ASTWES is a concise candidate questionnaire with preliminary evidence of a correlated three-domain structure, acceptable internal consistency, and short-term clinical association in Chinese adults aged 18–35 years. Further independent patient-centered content evaluation and external validation are needed before routine use or fixed decision thresholds are considered.