Validation and Use of Quality of life Impact of Refractive Correction Questionnaire in Spectacle Wearers in Malawi: A clinic-based study

Abstract

Background
To assess the psychometric properties of the QIRC questionnaire and use it as an outcome measure in spectacle wearers attending an eye clinic in Malawi.
Methods
Participants who had uncorrected distance visual acuity of below 6/18 and improved to 6/9 or better with spectacles on both eyes were included in the study. The participants self-administered the Chichewa version of the QIRC questionnaire that was translated and culturally adapted for Malawian settings. Psychometric evaluation of the QIRC responses was carried out using the WinSteps software (Version 3.92.1; Winsteps, Chicago, IL) by applying the Andrich rating scale model of the Rasch analysis.
Results
One hundred and forty-three participants (mean age ± standard deviation, 27.64 ± 2.91; age range; 16 to 39 years; male, 51.7%) completed the QIRC. The Chichewa QIRC had satisfactory psychometric properties (Ordered response categories, Person separation index, 1.93; Item separation index, 3.42; Targeting 0.70) including excellent Rasch-model fit statistics (Infit and Outfit MnSq < 1.30 for all items). The QIRC score was not significantly associated with sex, age, magnitude of refractive error, occupation and status of previous spectacle wear (p> 0.05 for all). The QIRC scores negatively correlated with uncorrected visual acuity (in logMAR) in the better eye (spearman’s rho=-0.34, p < 0.001).
Conclusions
The translated and culturally adapted version of the QIRC Questionnaire had satisfactory psychometric properties to measure the refractive error-specific quality of life in Malawi. It performed well as an outcome measure of spectacle wear.

Key words: validation, quality of life, Rasch analysis, spectacles, Malawi