Quality in Focus: Validation of a Sinhalese version of the Visual Function Questionnaire (VFQ)-25 for Sri Lankan populations

To validate a Sinhalese version of the VFQ-25 vision related quality of life assessment tool for use in Sri Lankan populations.

An instrument validation study was conducted at the National Eye Hospital, Colombo. All consenting patients with diabetic retinopathy who attended the clinics during the period of data collection were recruited until the expected sample size was met. Expert review of the translated questionnaire was done by a consultant vitreo-retinal surgeon and a specialist in ophthalmological research. Patient responses were used to assess internal consistency, inter-rater and test-retest reliability and construct validity. Content validity was ensured by expert review.

71 patients participated in the study of whom a majority were males (53.5%) and the mean age was 57.68 (± 9.429) years. The mean logMAR binocular single vision (BSV) and Eastermann scores were 0.803 (± 0.630) and 79.27 (±21.95) respectively. A high level of internal consistency as well as inter-rater and test-retest reliability overall and for each subscale was demons-trated, with an overall Cronbach alpha value of 0.953 for internal reliability. The overall score correlated with best corrected visual acuity (BCVA) of the better eye, BSV and Eastermann score demonstrating good construct validity.

The developed Sinhalese version of the VFQ-25 was proven to be a valid and reliable tool. It is the first ever complete vision related quality of life questionnaire to be validated for use in a Sri Lankan setting and will be of immense benefit to clinicians and academics for future studies.