The Vision Correction Questionnaire : an electronic patient-reported outcome measure for refractive surgery

PURPOSE: To develop a psychometrically robust electronic patient reported outcome measure (ePROM) for refractive surgery. SETTING: Moorfields Eye Hospital, London, United Kingdom. DESIGN: Questionnaire development study. METHODS: Items were derived in 6 domains (spectacle dependence, visual quality, eye comfort, functional freedom, emotional wellbeing, and satisfaction with treatment) from existing Rasch adjusted instruments, patient and surgeon feedback, and refinement in semistructured interviews before administration to a field test cohort (n = 360) of patients undergoing routine refractive surgery. Spectacle dependence and satisfaction with treatment items were used to provide descriptive statistical information only. Contemporary criteria for item reduction and Rasch modeling were applied to the remaining domains. The finalized questionnaire was then administered to a second patient cohort (n = 120) before and after surgery to assess sensitivity to change. RESULTS: A 5-item scale derived for emotional wellbeing was unidimensional and a good fit to the Rasch model with ordered category response profiles, adequate precision (person separation 2.22 logits, reliability coefficient 0.83), and no misfitting items. Mean logit scores were 0.91 higher after treatment (effect size 1.26) suggesting a positive impact on emotional wellbeing. Functional scales could not be derived for visual quality, eye comfort, or functional freedom. Single-item ratings for visual quality and eye comfort were retained in our final 11-item questionnaire. CONCLUSIONS: This short ePROM should integrate well with routine clinical care and clinical trials in refractive surgery. The Rasch adjusted emotional wellbeing scale may help quantify the way patients feel about refractive surgery, with the remaining items providing useful descriptive information