Abstract
Purpose: :
The overarching aim is to develop a comprehensive ophthalmic quality of life (QOL) item bank (the Eye-tem Bank) to enable the measurement of QOL parameters for all eye diseases across all populations. Here we present the early findings of Phases I and II.
Methods: :
The Eye-tem Bank is being developed in four phases across 10 disease groups: cataract & corneal opacities, glaucoma, diabetic retinopathy, age-related macular degeneration, vitreo-retinal disease, refractive error, strabismus, lacrimal & ocular surface disease, inflammation and neuro-ophthalmic disorders. The four phases are: Phase I: Content identification (items from existing questionnaires and disease-specific patient focus groups); Phase II: Pilot testing the initial item sets for item calibration using Rasch analysis; Phase III: Validation of the Eye-tem Bank implemented via a Computer Adaptive Testing (CAT) system; and Phase IV: Evaluating ophthalmic QOL using the Eye-tem bank.
Results: :
Phase I for the glaucoma and diabetic retinopathy (DR) groups has been completed. Focus groups were conducted with 72 glaucoma patients (median age, 63 years; range, 38-82 years) and 57 DR patients (median age, 58 years; range, 27-83 years). Items identified in focus groups were combined with existing items and refined to develop final sets of 349 and 314 items for glaucoma and DR, respectively; where focus groups contributed 249 and 120 novel items, respectively. The items were grouped across 10 domains (activity limitation, mobility, visual symptoms, ocular surface symptoms, general symptoms, convenience, health concerns, emotions, social and work/finance). Almost two-thirds of the items were common between these two disease groups (common, 218; unique glaucoma, 131; unique diabetic retinopathy, 96). A standard question (e.g. for activity limitation: how much difficulty do you have…) and response category (e.g. none/a little/quite a bit/a lot/to unable to do because of my vision) format was developed for each domain according to best available evidence. Phase II pilot data collection has commenced for the diabetic retinopathy (n=380) and glaucoma (n=5) groups. Disease-specific focus groups are being organised to develop comprehensive content for the 8 remaining disease groups.
Conclusions: :
The majority of the items were common between DR and glaucoma, a pattern likely to continue across all disease groups. Therefore, we hypothesise that the final Eye-tem Bank will have a core item set plus disease-specific items. Data from the pilot questionnaires will be calibrated with Rasch analysis and implemented via a CAT system to become the Eye-tem Bank: a system for the comprehensive measurement of ophthalmic QOL.
Keywords: quality of life • clinical research methodology • clinical (human) or epidemiologic studies: biostatistics/epidemiology methodology