Amblyopia and strabismus-specific quality of life ‘item banks’ for adults living in Australia and India – item generation and comparison

Abstract

Purpose : We are developing item banks to measure the quality of life (QoL) impact of amblyopia and strabismus on adults. This paper reports the results of Phase 1: construction of country-specific item pools for Australian and Indian populations. We examine the items (QoL issues) that are common to both countries and explore the possibility of a universal item pool.

Methods : Items were first drawn from existing amblyopia and strabismus specific questionnaires (n=22) and published qualitative studies (n=5). Next, an extensive qualitative study was carried out in Australia with adults, aged over 18 years, living with amblyopia and/or strabismus (n=49). NVivo 11 software was used for qualitative analysis and item extraction. The initial item pool was refined and revised to obtain an optimal set of representative items (Australian pool). A similar study was replicated in Tamil Nadu, India (n=30) in Tamil and English. Qualitative analysis of Indian data and item extraction was performed in English, using the Australian item pool as framework; some items were added, some deleted and some were reworded based on expert opinion and cognitive interviews. The Indian item pool was then translated to Tamil and Hindi languages by standard forward, backward translation and expert opinion.

Results : The initial Australian item pool consisted of 930 items, which was reduced to an optimal representative set of 312 items. Seventeen items were added, 52 items deleted and 44 items re-worded to form the Indian item pool (n=277). 260 items (79%) were common to both countries; the number of common items in each QoL domain were symptoms (31), activity limitation (49), mobility (12), health concerns (55), emotional well-being (37), social well-being (20), convenience (24), economic impact (12) and coping (20). The Australian pool had more items in every domain; emotional well-being (24.09%), activity limitations (19.74%) and coping (16.67%) had highest percentage of unique items.

Conclusions : Amblyopia and strabismus specific QoL item pools for Australia and India have been developed. Items that are common to both countries were identified. In the next phase, data collected on these items will undergo Rasch analysis, country-specific item calibrations and the common item pool will be tested for any differential item functioning.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.