Dataset Information

Psychometric properties of the Greek version of the NEI-VFQ 25.

ABSTRACT:

Background

To evaluate the reliability and construct validity of a Greek version of the NEI-VFQ-25 in patients with chronic ophthalmic diseases.

Methods

We developed the Greek version of the instrument using forward and backward translation. One hundred-eighty-six patients responded to the questionnaire. To examine reliability, Cronbach's alpha for each subscale was used as an index of internal consistency. Test-retest reliability was evaluated with intraclass correlation coefficients. Regarding construct validity, both convergent and discriminant validities were calculated by means of multi-trait analysis. Rasch analysis was used to estimate the visual ability required by each item for a particular response, and each patient's visual ability. Correspondingly, instrument validity was evaluated by estimating the distribution of residuals for item and subject measures.

Results

Four patient groups were studied, each including participants with a single cause of visual impairment. Group 1 consisted of 84 glaucoma subjects. Group 2 included 30 subjects with age-related macular degeneration (ARMD); group 3 included 25 subjects with dry-eye syndrome, whereas group 4 included 18 cataract patients. Twenty-nine healthy individuals comprised the control group. NEI-VFQ scores (mean +/- SD) for the glaucoma, ARMD, dry-eye, cataract and control groups were: 76.9 +/- 20.2, 70.9 +/- 20.2, 81.6 +/- 16.5, 73.5 +/- 24.0 and 93.7 +/- 8.9 respectively. Item analysis revealed no significant data skewing. Cronbach's alpha ranged from 0.678 to 0.926, with most subscales having high internal consistency. Intraclass correlation coefficient ranged from 0.717 to 0.910 for all subscales. All items passed the convergent and discriminant validity tests. Strong correlations were detected between visual acuity and "general vision", "distant activities" and "near activities" subscales. Significant correlations were also detected between visual field deficits and the "peripheral vision" and "general vision" subscales. Rasch analysis revealed potential weaknesses of the instrument that are associated with the assumptions of the model itself. Specifically, low precision of the "agreement" items was detected in the estimation of visual ability. Twenty-three percent of the subjects had fit statistics that fell outside the tolerance box.

Conclusion

Although traditional validation methods indicated that the Greek version of the NEI-VFQ-25 is a valid and reliable instrument for VS-QoL assessment, Rasch analysis detected significant misfits to the model, especially of the "agreement" items. This means that results of the corresponding subscales should be interpreted with extreme caution.

SUBMITTER: Labiris G

PROVIDER: S-EPMC2287166 | biostudies-literature | 2008 Mar

REPOSITORIES: biostudies-literature

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Publications

Psychometric properties of the Greek version of the NEI-VFQ 25.

Labiris Georgios G Katsanos Andreas A Fanariotis Michael M Tsirouki Theodora T Pefkianaki Maria M Chatzoulis Dimitrios D Tsironi Evangelia E

BMC ophthalmology 20080306

<h4>Background</h4>To evaluate the reliability and construct validity of a Greek version of the NEI-VFQ-25 in patients with chronic ophthalmic diseases.<h4>Methods</h4>We developed the Greek version of the instrument using forward and backward translation. One hundred-eighty-six patients responded to the questionnaire. To examine reliability, Cronbach's alpha for each subscale was used as an index of internal consistency. Test-retest reliability was evaluated with intraclass correlation coeffici ...[more]

PMID: 18325083

Similar Datasets

Project description:BACKGROUND:To investigate the psychometric properties of the Brazilian Portuguese version of the National Eye Institute Visual Function Questionnaire (NEI VFQ-25) questionnaire in a group of patients with different eye diseases. METHODS:Cross-sectional study. All subjects completed the Portuguese version of the NEI VFQ-25 questionnaire. Another questionnaire containing a survey about clinical and demographics data was also applied. Rasch analysis was used to evaluate the psychometric properties of the NEI VFQ-25. RESULTS:The study included 104 patients with cataract, 65 with glaucoma and 83 with age macular degeneration. Mean age was 70.7 ± 9.9 years, with 143 female (56.7%) and 109 male patients (43.2%). Mean visual acuity was 0.47 and 1.17 logMAR in the better and worse eye, respectively. According to Rasch analysis, seven items were found to misfit. Those items belonged to the following subscales: general health, social function, mental health, ocular pain and role limitations. The principal component analysis of the residuals showed that 55.5% of the variance was explained by the principal component. Eight items loaded positively onto the first contrast with a correlation higher than 0.4. These items belonged to the following subscales: near vision, distance vision, mental health and dependency. After excluding those items, we were able to isolate items from the NEI VFQ-25, related only to a visual functioning component. Finally, the principal component analysis from residuals of this revised version of the NEI VFQ-25 (items related to visual function) showed that the principal component explained 61.2% of the variance, showing no evidence of multidimensionality. CONCLUSIONS:The Portuguese version of the NEI VFQ-25 is not a unidimensional instrument. We were able to find items that belong to a different trait, possible related to a socio-emotional component. Thus, in order to obtain psychometrically valid constructs, both the visual functioning and socio-emotional components should be analyzed separately.

Project description:To estimate the burden of diseases, it is important to consider patient-reported outcomes including Quality of Life (QoL). The aim of this study is to provide population-based reference data for the National Eye Institute 25-Item Visual Function Questionnaire (NEI VFQ-25), stratified by sex and age.The Gutenberg Health Study (GHS) is a population-based, prospective, observational cohort study in Germany, including 15,010 participants aged between 35 and 74. The baseline examination was conducted between 2007 and 2012. To overcome known shortcomings of the NEI VFQ-25, we calculated the previously proposed visual functioning scale and the socio-emotional scale based on Rasch-transformed person-level data. We present mean values, standard deviations and percentiles for age decades stratified by sex. We used a linear regression model to assess the influence of age, sex, socioeconomic status, distance-corrected visual acuity (better-seeing eye) and the absolute difference in distance-corrected visual acuity of both eyes on vision-related QoL.NEI VFQ-25 data are available from 12,231 participants (82%). Both the long-form visual functioning scale (LFVFS) and the long-form socio-emotional scale (LFSES) showed a clear age dependency, with an average LFVFS score of 92.8 for men and 90.5 for women in the youngest age group and 85.7 and 83.4 in the oldest age group, and a LFSES score of 98.3 for men and 98.1 in women in the youngest and 94.7 and 94.5 in the oldest decade. The largest difference was observed between the youngest age group (35-44 years) and the 45-54 years group. Men tended to have slightly higher scores than women. In the multivariable linear regression analysis, age (per 5 years -0.42), female sex (-1.57), worse distance-corrected visual acuity of the better eye (per 0.1 increase in logMAR -2.92) and the difference between both eyes (per 0.1 increase in logMAR -0.87) were associated with a reduced LFVFS score (all p < 0.001). For the LFSES score, we showed that the influence of sex was minor, and that age (per 5 years -0.22), visual acuity of the better eye (-1.65), and the difference between both eyes (-0.56) were associated with a lower score (all p < 0.001).We report age- and sex-specific reference data from a large population-based study of mainly Caucasian ethnicity of two unidimensional scores based on Rasch-transformed NEI VFQ-25 data. Vision-related QoL is lower in older and in female individuals. Our results support the association of vision-related QoL not only with the distance-corrected visual acuity of the better eye but also with the difference in visual acuity between each eye. Our findings could be used as a reference for comparison in future studies addressing the influence of eye diseases on vision-related QoL.

Dataset Information

Psychometric properties of the Greek version of the NEI-VFQ 25.

Background

Methods

Results

Conclusion

Publications

Psychometric properties of the Greek version of the NEI-VFQ 25.

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