Validity and reliability study of Turkish version on low vision with quality of life questionnaire

To adapt the low vision-related quality of life (LVQOL) instrument into Turkish language and to assess its validity and reliability.

The study was conducted in 387 patients attending the Centre of Low Vision Rehabilitation, Faculty of Medicine, Ankara University. For statistical analyses, the Spearman's correlation coefficient, Cronbach's alpha coefficient and Confirmatory Factor Analysis (CFA) were used.

According to results of CFA, the item in the "Adjustment" subscale because of having the factor loading below 0.40, was excluded from the questionnaire. The reliability of the questionnaire was assessed according to Cronbach's alpha coefficients. The reliability of the "Distance Vision, Mobility, and Lighting" subscale was α=0.863; of the "Adjustment" subscale wasα=0.694; "Reading and Fine Work" wasα=0.791, and "Activities of Daily Living" was α=0.770. So these results indicate that the questionnaire is reliable to measure the vision related quality of life of low-vision patients. The correlations between the subscales were also analyzed, and the correlation between "Adjustment" and "Reading and Fine Work" was found to be the lowest (r(s)=0.336, P<0.001), whereas the strongest correlation was found between the "Reading and Fine Work", and "Activities of Daily Living". Additionally, the "Adjustment" dimension showed the strongest correlation with only "Distance Vision, Mobility, and Lighting" dimension.

After removing the last item in the second dimension, the Turkish adaptation of all dimensions of the LVQOL has been shown to be reliable, valid and suitable for use in patients with low vision in Turkey.