- Email: [email protected]
Crosscultural adaptation and validation into Spanish of the questionnaire National Eye Institute Visual Function Questionnaire 25
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ARCHIVOS DE LA SOCIEDAD ESPAÑOLA DE OFTALMOLOGÍA www.elsevier.es/oftalmologia
Original article
Crosscultural adaptation and validation into Spanish of the questionnaire National Eye Institute Visual Function Questionnaire 25夽 C. Alvarez-Peregrina a , M.A. Sánchez-Tena a,∗ , D. Caballé-Fontanet a , I.J. Thuissard-Vasallo a , M.B. Gacimartín-García b , C. Orduna-Magán b a b
Universidad Europea de Madrid, Madrid, Spain Clínica Oftalmológica Orduna, Madrid, Spain
a r t i c l e
i n f o
a b s t r a c t
Article history:
Introduction: Advances in medicine have contributed to a higher average life expectancy, as
Received 20 February 2018
well as an increasing number of chronic diseases patients. This longevity means that the
Accepted 22 May 2018
assessment of the quality of life, particularly that related to vision, has become very relevant.
Available online xxx
Objective: The validation of the translation and cross-cultural adaptation into Spanish of one of the most widely used vision-related quality of life questionnaires. It has sought to ensure
Keywords:
that the Spanish version of the questionnaire was equivalent in semantic, conceptual, and
Quality of life
technical content and criteria level, compared to its already validated English version.
Questionnaire
Method: An analytical observational study was conducted using a cohort of patients, in
National Eye Institute Visual
whom their quality of life related to vision was analyzed. The study was developed in two
Function Questionnaire 25
steps; the first was the translation and cross-cultural adaptation to Spanish of the NEI VFQ-
Vision
25 questionnaire. The second one was the psychometric study of the reliability and validity of the scale of the Spanish version. Results: The analysis of the terms of reliability and validity showed that the translation and cross-cultural adaptation met the expected requirements and was well accepted by users. Conclusion: There is now a possibility of having a Spanish validated questionnaire available to assess the quality of life related to vision in patients with chronic diseases, such as agerelated macular degeneration. ˜ ˜ S.L.U. All rights © 2018 Sociedad Espanola de Oftalmolog´ıa. Published by Elsevier Espana, reserved.
夽 Please cite this article as: Alvarez-Peregrina C, Sánchez-Tena MA, Caballé-Fontanet D, Thuissard-Vasallo IJ, Gacimartín-García MB, Orduna-Magán C. Adaptación cultural y validación al castellano del cuestionario National Eye Institute Visual Function Questionnaire 25. Arch Soc Esp Oftalmol. 2018. https://doi.org/10.1016/j.oftal.2018.05.017 ∗ Corresponding author. E-mail address: [email protected] (M.A. Sánchez-Tena). ˜ ˜ S.L.U. All rights reserved. 2173-5794/© 2018 Sociedad Espanola de Oftalmolog´ıa. Published by Elsevier Espana,
OFTALE-1357; No. of Pages 6
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Adaptación cultural y validación al castellano del cuestionario National Eye Institute Visual Function Questionnaire 25 r e s u m e n Palabras clave:
Introducción: Los avances en medicina han contribuido al aumento del promedio de vida,
Calidad de vida
existiendo un mayor número de pacientes crónicos. Esto hace que la evaluación de la calidad
Cuestionario
de vida de los pacientes en varios aspectos, entre ellos el relacionado con su visión, haya
National Eye Institute Visual
adquirido una especial importancia.
Function Questionnaire 25
Objetivo: Validación de la traducción y adaptación cultural al castellano de uno de los cues-
Visión
tionarios de calidad de vida relacionada con la visión más ampliamente empleados. Se ha buscado que el cuestionario en castellano sea equivalente semántica y conceptualmente, así como de contenido técnico y de criterio que el ya validado en inglés. Método: Estudio observacional analítico de una cohorte de pacientes en los que se ha analizado la calidad de vida relacionada con la visión. El estudio se ha desarrollado en 2 fases, una primera de traducción y adaptación cultural al castellano del cuestionario NEI VFQ-25 y, la segunda, de estudio psicométrico de la fiabilidad y validez de la escala en la versión en castellano. Resultados: El análisis de fiabilidad y validez refleja que la traducción y adaptación cultural cumple con los requisitos esperados y ha sido bien aceptada por los usuarios. Conclusión: Se puede disponer de un cuestionario validado en castellano para evaluar la calidad de vida en pacientes con enfermedades crónicas como la degeneración macular asociada a la edad. ˜ ˜ S.L.U. Todos de Oftalmolog´ıa. Publicado por Elsevier Espana, © 2018 Sociedad Espanola los derechos reservados.
Introduction and objectives The World Health Organization defines health not only as the absence of disease but as a state of physical, mental and social welfare. The importance of including quality of life assessments in daily clinic practice is increasing with the adoption of the patient-centered model. This has led to increased use of questionnaires for measuring patient quality of life.1 In ophthalmology, the degree of success was measured by morbidity/mortality or visual acuity/visual field.2 At present, developments in medicine have contributed to increased average lifespans leading to higher numbers of chronic patients. This has enhanced the value of measuring vision-related quality of life.3–5 At present, several validated tests5–7 endeavor to measure and compare patient information for quality of life assessments.8 Specifically, the National Eye Institute Visual Function Questionnaire 25 (NEI VFQ-25) is used with increasing frequency in vision sciences.9 This questionnaire was developed in the United States and has been validated for several diseases including age-related macular degeneration (AMD),10,11 glaucoma,12 diabetic retinopathy,13 dry eye,14 blepharospasm,15 pigment retinitis,16 and uveitis.17 It has been translated, adapted to the cultural environment and validated in the following languages: Serbian,7 Turkish,5 Chinese,4 Japanese,18 Greek,19 French,20 Italian,21 Polish,22 Portuguese,23 and Spanish,24 although the latter translation is based on the Latin American style of use. The main objective of this study is to validate the translation to Spanish and its cultural adaptation to Spain. This is
justified because the lack of said adaptation could give rise to errors in its application, including diagnostic, therapy types, epidemiological records or public policies, in addition to unreliable results between studies of different authors.25
Material and methods An observational and analytic study of a cohort of patients with ocular disease. A convenience sampling was carried out in the Orduna Ophthalmologic Clinic of Madrid and in the Visión Opticians of Manresa (Barcelona). Vision-related quality of life was analyzed in the following 2 phases: - Phase 1: translation and cultural adaptation of the NEI VFQ25 questionnaire. - Phase 2: psychometric study of the reliability and validity of the scale in the European Spanish version. The study was carried out in accordance with the principles established by the Helsinki declaration and was approved by the ethics committee. The methodology applied in the study was based on the recommendations by Ramada-Rodilla et al.25 The NEI VFQ-25 questionnaire comprises a number of scores: general health (1 item), general vision (1 item), ocular pain (2 items), near vision difficulty (3 items), difficulties in far vision activities (3 items), social limitations due to vision (2 items), mental problems due to vision (4 items), role problems due to vision (2 items), dependency (3 items), difficulties
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driving vehicles (2 items), color vision problems (1 item) and peripheral vision difficulties (1 item). Each subcategory involves a score, with the final score being comprised between 0 and 100. Higher scores corresponds to better quality of life results.26,27
Phase 1 methodology. Translation and cultural adaptation The objective of the translation and adaptation to European Spanish of the NEI VFQ-25 questionnaire was to make the instrument equivalent at the semantic, conceptual, technical and approach in the Spanish language. To this end, 4 steps were followed, each based on different techniques.
Step I: direct translation A translation from English to Spanish with the involvement of 2 independent bilingual translators having European Spanish as mother tongue. One of the translators was an optician-optometrist and the other was a professional translator without previous knowledge of the questionnaire.
Step II: synthesis of translations Both translations were compared in order to identify and discuss possible discrepancies and reach an agreed-upon version.
Step III: inverse translation The agreed-upon version was again translated into English with the participation of 2 independent bilingual translators with English as mother tongue. One of the translators was a vision specialist and both did not know the original version of the questionnaire. They were requested to underline the difficulties they encountered in the course of the translation. Subsequently, both translations were analyzed to determine the existence of significant semantic or conceptual differences reaching the original questionnaire and the inversely translated versions.
Table 1 – Study patient characteristics. n = 96 Patient age, mean ± SD
71.0 ± 11.0
Sex Males, n (%) Females, n (%)
46 (47.91) 50 (52.09)
Classification based on vision VA >0.3. n (%) VA 0.3–0.1. n (%) VA <0.1. n (%) General healtha , mean ± SD General visiona , mean ± SD Ocular paina , mean ± SD Near activitiesa , mean ± SD Far activitiesa , mean ± SD Social performancea , mean ± SD Mental healtha , mean ± SD Role difficultiesa , mean ± SD Dependencya , mean ± SD Drivinga , mean ± SD Color visiona , mean ± SD Peripheral visiona , mean ± SD
66 (68.8) 20 (20.8) 10 (10.4) 48.0 ± 29.4 52.0 ± 22.9 79.6 ± 22.2 71.2 ± 30.7 72.4 ± 32.0 80.9 ± 30.0 67.2 ± 31.2 67.3 ± 37.8 76.5 ± 34.6 88.3 ± 12.6 86.6 ± 26.6 80.9 ± 29.6
a
Questionnaire score range: 0–100.
sample utilized for the validity criteria applied by the authors of the scale.28 Demographic variables (age, sex) of patients were obtained on the basis of their clinical records after obtaining their authorization and signature of informed consents. Visual acuity (VA) was analyzed, classifying the sample in 3 groups based on the definition of poor vision (binocular VA with best offsetting) and legal blindness (binocular VA with best offsetting <0.1). The NEI VFQ-25 questionnaire was given to the patients for filling in and subsequent study.
Statistical analysis Step IV: consultation by an expert committee A committee with 3 vision experts, a methodologist and the translators was established with the aim of obtaining a consolidated questionnaire adapted to European Spanish. The committee had the direct translations (step 1), the summarized version (step 2) and the inverse translations (step 3) and discussed the discrepancies that were identified. Special attention was given to any difficulty in the understanding of the questions.
Phase II methodology: psychometric reliability and validity study The individuals who took part in the study were over 21 years of age, having Spanish as mother tongue and had the ability to respond to a questionnaire filling in answers to questions and having one of the following ocular conditions: AMD, diabetic retinopathy, open angle primary glaucoma or retinitis due to cytomegalovirus, or with poor vision without a diagnosed cause. A convenience sampling was selected to assess the psychometric properties of the instrument until a size of 96 patients was reached. The objective of the sample was to replicate the
Descriptive statistics of the analyzed variables were carried out, expressing said variables as mean ± standard deviation (SD) or median (interquartile range) based on the parametric performance thereof. For qualitative variables, absolute (n) and relative (%) frequencies were utilized. Questionnaire reliability was analyzed by means of internal consistency. Validity analysis took into account the validity of the contents and the construct. Statistical analyses were carried out with the SPSS application (version 21.0; IBM Corp, Armonk, NY, USA).
Results Table 1 describes the demographic and clinical characteristics of the 96 patients who completed to be NEI VFQ-25 questionnaire in its European Spanish version as well as the score obtained in each item evaluated therein. The mean age of patients was 71.0 ± 11.0 years, with similar distribution between 47.91% of males and 52.09% of females. For scorings based on vision, nearly 70% with very good vision was obtained. The study subjects produced a general
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Table 2 – Subscale reliability analysis.
General health General vision Ocular pain Near activities Far activities Social performance Mental health Role difficulties Dependency Driving Color vision Peripheral vision
Assessable cases (n)
Scorea (mean ± SD)
Cronbach alpha (CI 95%)
96 96 96 96 96 96 96 96 96 38 96 96
48.00 52.00 79.58 71.16 72.40 80.94 67.20 67.25 76.54 88.27 86.63 80.94
± ± ± ± ± ± ± ± ± ± ± ±
NA NA 0.769 (0.654–0.845) 0.926 (0.896–0.948) 0.913 (0.877–0.940) 0.906 (0.861–0.937) 0.868 (0.819–0.906) 0.949 (0.924–0.966) 0.937 (0.911–0.956) 0.594 (0.299–0.777) NA NA
29.45 22.92 22.20 30.71 31.98 29.98 31.24 37.81 34.64 12.63 26.59 29.61
NA: could not be assessed due to having only one item. a
Questionnaire score range: 0–100. Analysis of main components Sedimentation Graph Extraction
4.5 General health
0,697
General vision
0,656
Ocular pain
0,583
Near activities
0,785
Far activities
0,883
Social performance
0,699
Mental health
0,833
Role difficulties
0,910
Dependency
0,851
1.0
Driving
0,650
0.5
Color vision
0,809
Peripheral vision
0,759
4.0
Autovalues
3.5 3.0 2.5 2.0 1.5
0.0 1
2
3
4
5
6
7
8
9
10 11 12
Component number
Fig. 1 – Sedimentation graph with analysis of main components.
health score below 50 points and in the area of 52 for general vision. As can be seen in Table 1, the scores obtained for the rest of items were close to 70 or greater, the highest being for driving (Table 1).
In general, it was observed that the scores for the general health and vision items were the lowest, in the area of 50 points. In contrast, the rest of items obtained scores close to or even above 70 points (Table 2).
Validity Reliability Overall, 96 questionnaires were analyzed. NEI VFQ-25 (European Spanish version) reliability, calculated on the basis of the Cronbach alpha coefficient for all 12 items, was 0.831 (CI 95%: 0.735–0.904). The elimination of none of the items produced an increase of over 0.10 points compared to the global coefficient. The corrected element-total correlations did not exhibit negative values and, out of the 10 questions having a value under 0.30; only question 3 was under 0.22. Reliability analysis for subscales (Table 2) showed homogeneity with values above Cronbach alpha 0.7 in all cases with the exception of driving that achieved a value of 0.594. This value matched the results obtained in other studies carried out with the original version because the question concerns an activity that can be carried out adequately or not at all and obtained only 38 responses, well below the 96 responses obtained for the rest of items. This explains its lower value.
The Kaiser Meyer Olkim test, obtained from the analyzed questionnaires, showed a value of 0.674, indicating that the ratio between items was lower. Even so, Bartlett’s sphericity test provided a value of p < 0.001, which means that the factorial analysis was adequate despite the presence of many subscales that are not adequately represented in the factorial solution (general health and vision, ocular pain and driving). Fig. 1 shows the analysis of the main components together with the sedimentation graph where it can be appreciated that the first 4 items collect almost 76% of aggregate variability (Fig. 1). Table 3 shows the difference between the various groups, classified on the basis of VA: - Best corrected binocular VA >0.3. - Best corrected binocular VA 0.3–0.1. - Best corrected binocular VA <0.1.
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Table 3 – Comparison of variables based on a visual acuity. VA >0.3 N = 66 General healtha General visiona Ocular paina Near activitiesa Far activitiesa Social performancea Mental healtha Role difficultiesa Dependencya Drivinga Color visiona a
52.60 59.41 86.05 82.36 84.72 93.11 80.25 92.21 87.61 95.65 88.04
± ± ± ± ± ± ± ± ± ± ±
29.00 20.72 17.00 22.12 21.66 13.81 21.40 18.020 12.65 14.19 22.93
VA 0.3–0.1 N = 20
VA <0.1 N = 10
35.0 ± 23.5 37.0 ± 16.26 69.38 ± 26.12 56.87 ± 7.95 55.00 ± 31.19 63.75 ± 3315 43.43 ± 31.57 52.50 ± 36.38 – 77.50 ± 34.31 77.50 ± 31.30
40.00 32.00 55.00 23.33 22.50 30.00 30.00 20.83 – 45.00 42.50
± ± ± ± ± ± ± ±
p value
37.6 25.30 23.71 3.38 31.19 30.16 31.70 33.61
± 30.73 ± 35.45
0.026 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 – <0.01 <0.01
Questionnaire score range: 0–100.
It can be seen that, as expected, the score for all questionnaire items was higher in patients having better vision. Accordingly, patients having better vision have a higher quality of life score (Table 3).
Discussion The translation of the NEI VFQ-25 questionnaire to Spanish and specific cultural adaptation to Spain has become a pioneering initiative in our country. This will avoid problems in the understanding of the questionnaire and obtain more objective and reliable data to improve the follow-up of the quality of life of patients affected with diseases such as AMD, diabetic retinopathy, open angle primary glaucoma or retinitis due to cytomegalovirus or with poor vision without a diagnosed cause. The reliability and validity results show that said translation and cultural adaptation fulfills expected requirements and was well accepted by users. When compared with the original questionnaire28 the results are similar and comparable, and accordingly it can be stated that its utilization in daily clinic practice in Spain is justified as an easy and validated method to determine the quality of life of patients and follow-up any changes therein regardless of the results obtained in other objective questionnaires. This is essential for some degenerative diseases such as AMD which is increasingly predominant in the population. Comparing each item with the Latin American Spanish translation24 it can be seen that some questions that gave rise to doubts in the previous translation are much clearer in the version developed by this study. In fact, cultural adaptation and translation to Spanish has provided a clear and objective tool to measure quality of life changes in patients who, even though were not able to improve their visual acuity, have improved in carrying out daily life activities related to vision.
Conflict of interests The authors state the absence of any potential conflict of interests related to this article.
Acknowledgments The authors wish to express their gratitude to Dr. Pablo Gili for his support in the early stages of this study and to Professor David Sanz Rosa of the European University for generously contributing his time and judgment during the development of the questionnaire.
Appendix A. Supplementary data Supplementary data associated with this article can be found in the online version at doi:10.1016/j.oftale.2018.09.001.
references
1. Yuzawa M, Fujita K, Tanaka E, Wang ECY. Assessing quality of life in the treatment of patients with age-related macular degeneration: clinical research findings and recommendations for clinical practice. Clin Ophthalmol. 2013;7:1325–32. 2. Laine C, Davidoff F. Patient-centered medicine. A professional evolution. JAMA. 1996;275:152–6. 3. Clancy CM, Eisenberg JM. Outcomes research: measuring the end results of health care. EBSCOhost. 1998;282:245–6. 4. Lin JC, Chie WC. Psychometric validation of the Taiwan Chinese version of the 25-Item National Eye Institute Visual Functioning Questionnaire. J Eval Clin Pract. 2009;16:619–26. 5. Mollazadegan K, Huang J, Khadka J, Wang Q, Yang F, Gao R, et al. Cross-cultural validation of the National Eye Institute Visual Function Questionnaire. J Cataract Refract Surg. 2014;40:774–84. 6. Massof RW, Rubin GS. Visual function assessment questionnaires. Surv Ophthalmol. 2001;45:531–48. 7. Kovac B, Vukosavljevic M, Djokic Kovac J, Resan M, Trajkovic G, Jankovic J, et al. Validation and cross-cultural adaptation of the National Eye Institute Visual Function Questionnaire (NEI VFQ-25) in Serbian patients. Health Qual Life Outcomes. 2015;13:142. 8. García de Yébenes Prous MJ, Rodríguez Salvanés F, Carmona Ortells L. Validación de cuestionarios. Reumatol Clín. 2009;5:171–7. 9. Pérez Jiménez D, Lupón Bas M. Evaluación de la calidad de vida relacionada con la visión. Gac Optom y Óptica Oftálmica. 2017;521:60–4.
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10. Orr P, Rentz AM, Margolis MK, Revicki DA, Dolan CM, Colman S, et al. Validation of the National Eye Institute Visual Function Questionnaire-25 (NEI VFQ-25) in Age-Related Macular Degeneration. Invest Ophthalmol Vis Sci. 2011;52:3354. 11. Cahill M, Banks A, Stinnett S, Toth C. Vision-related quality of life in patients with bilateral severe age-related macular degeneration. Ophthalmology. 2005;112:152–8. 12. Jampel HD, Schwartz A, Pollack I, Abrams D, Weiss H, Miller R. Glaucoma patients’ assessment of their visual function and quality of life. J Glaucoma. 2002;11:154–63. 13. Cusick M, Sangiovanni JP, Chew EY, Csaky KG, Hall-Shimel K, Reed GF, et al. Central visual function and the NEI-VFQ-25 near and distance activities subscale scores in people with type 1 and 2 diabetes. Am J Ophthalmol. 2005;139:1042–50. 14. Nichols KK, Mitchell GL, Zadnik K. Performance and repeatability of the NEI-VFQ-25 in patients with dry eye. Cornea. 2002;21:578–83. 15. Hall TA, McGwin G, Searcey K, Xie A, Hupp SL, Owsley C, et al. Health-related quality of life and psychosocial characteristics of patients with benign essential blepharospasm. Arch Ophthalmol. 2006;124:116. 16. Burstedt MSI, Mönestam E, Sandgren O. Associations between specific measures of vision and vision-related quality of life in patients with bothnia dystrophy, a defined type of retinitis pigmentosa. Retina. 2005;25:317–23. 17. Mello Pra AP, Roma AC, Moraes Júnior HV. Análise da qualidade de vida de portadores de uveítes de causas infecciosas e não infecciosas pelo questionário NEI-VFQ-25. Arq Bras Oftalmol. 2008;71:847–54. 18. Suzukamo Y, Oshika T, Yuzawa M, Tokuda Y, Tomidokoro A, Oki K, et al. Psychometric properties of the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25), Japanese version. Health Qual Life Outcomes. 2005;3:65. 19. Labiris G, Katsanos A, Fanariotis M, Tsirouki T, Pefkianaki M, Chatzoulis D, et al. Psychometric properties of the Greek version of the NEI-VFQ 25. BMC Ophthalmol. 2008;8:4.
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ARCHIVOS DE LA SOCIEDAD ESPAÑOLA DE OFTALMOLOGÍA www.elsevier.es/oftalmologia
Original article
Crosscultural adaptation and validation into Spanish of the questionnaire National Eye Institute Visual Function Questionnaire 25夽 C. Alvarez-Peregrina a , M.A. Sánchez-Tena a,∗ , D. Caballé-Fontanet a , I.J. Thuissard-Vasallo a , M.B. Gacimartín-García b , C. Orduna-Magán b a b
Universidad Europea de Madrid, Madrid, Spain Clínica Oftalmológica Orduna, Madrid, Spain
a r t i c l e
i n f o
a b s t r a c t
Article history:
Introduction: Advances in medicine have contributed to a higher average life expectancy, as
Received 20 February 2018
well as an increasing number of chronic diseases patients. This longevity means that the
Accepted 22 May 2018
assessment of the quality of life, particularly that related to vision, has become very relevant.
Available online xxx
Objective: The validation of the translation and cross-cultural adaptation into Spanish of one of the most widely used vision-related quality of life questionnaires. It has sought to ensure
Keywords:
that the Spanish version of the questionnaire was equivalent in semantic, conceptual, and
Quality of life
technical content and criteria level, compared to its already validated English version.
Questionnaire
Method: An analytical observational study was conducted using a cohort of patients, in
National Eye Institute Visual
whom their quality of life related to vision was analyzed. The study was developed in two
Function Questionnaire 25
steps; the first was the translation and cross-cultural adaptation to Spanish of the NEI VFQ-
Vision
25 questionnaire. The second one was the psychometric study of the reliability and validity of the scale of the Spanish version. Results: The analysis of the terms of reliability and validity showed that the translation and cross-cultural adaptation met the expected requirements and was well accepted by users. Conclusion: There is now a possibility of having a Spanish validated questionnaire available to assess the quality of life related to vision in patients with chronic diseases, such as agerelated macular degeneration. ˜ ˜ S.L.U. All rights © 2018 Sociedad Espanola de Oftalmolog´ıa. Published by Elsevier Espana, reserved.
夽 Please cite this article as: Alvarez-Peregrina C, Sánchez-Tena MA, Caballé-Fontanet D, Thuissard-Vasallo IJ, Gacimartín-García MB, Orduna-Magán C. Adaptación cultural y validación al castellano del cuestionario National Eye Institute Visual Function Questionnaire 25. Arch Soc Esp Oftalmol. 2018. https://doi.org/10.1016/j.oftal.2018.05.017 ∗ Corresponding author. E-mail address: [email protected] (M.A. Sánchez-Tena). ˜ ˜ S.L.U. All rights reserved. 2173-5794/© 2018 Sociedad Espanola de Oftalmolog´ıa. Published by Elsevier Espana,
OFTALE-1357; No. of Pages 6
ARTICLE IN PRESS 2
a r c h s o c e s p o f t a l m o l . 2 0 1 8;x x x(x x):xxx–xxx
Adaptación cultural y validación al castellano del cuestionario National Eye Institute Visual Function Questionnaire 25 r e s u m e n Palabras clave:
Introducción: Los avances en medicina han contribuido al aumento del promedio de vida,
Calidad de vida
existiendo un mayor número de pacientes crónicos. Esto hace que la evaluación de la calidad
Cuestionario
de vida de los pacientes en varios aspectos, entre ellos el relacionado con su visión, haya
National Eye Institute Visual
adquirido una especial importancia.
Function Questionnaire 25
Objetivo: Validación de la traducción y adaptación cultural al castellano de uno de los cues-
Visión
tionarios de calidad de vida relacionada con la visión más ampliamente empleados. Se ha buscado que el cuestionario en castellano sea equivalente semántica y conceptualmente, así como de contenido técnico y de criterio que el ya validado en inglés. Método: Estudio observacional analítico de una cohorte de pacientes en los que se ha analizado la calidad de vida relacionada con la visión. El estudio se ha desarrollado en 2 fases, una primera de traducción y adaptación cultural al castellano del cuestionario NEI VFQ-25 y, la segunda, de estudio psicométrico de la fiabilidad y validez de la escala en la versión en castellano. Resultados: El análisis de fiabilidad y validez refleja que la traducción y adaptación cultural cumple con los requisitos esperados y ha sido bien aceptada por los usuarios. Conclusión: Se puede disponer de un cuestionario validado en castellano para evaluar la calidad de vida en pacientes con enfermedades crónicas como la degeneración macular asociada a la edad. ˜ ˜ S.L.U. Todos de Oftalmolog´ıa. Publicado por Elsevier Espana, © 2018 Sociedad Espanola los derechos reservados.
Introduction and objectives The World Health Organization defines health not only as the absence of disease but as a state of physical, mental and social welfare. The importance of including quality of life assessments in daily clinic practice is increasing with the adoption of the patient-centered model. This has led to increased use of questionnaires for measuring patient quality of life.1 In ophthalmology, the degree of success was measured by morbidity/mortality or visual acuity/visual field.2 At present, developments in medicine have contributed to increased average lifespans leading to higher numbers of chronic patients. This has enhanced the value of measuring vision-related quality of life.3–5 At present, several validated tests5–7 endeavor to measure and compare patient information for quality of life assessments.8 Specifically, the National Eye Institute Visual Function Questionnaire 25 (NEI VFQ-25) is used with increasing frequency in vision sciences.9 This questionnaire was developed in the United States and has been validated for several diseases including age-related macular degeneration (AMD),10,11 glaucoma,12 diabetic retinopathy,13 dry eye,14 blepharospasm,15 pigment retinitis,16 and uveitis.17 It has been translated, adapted to the cultural environment and validated in the following languages: Serbian,7 Turkish,5 Chinese,4 Japanese,18 Greek,19 French,20 Italian,21 Polish,22 Portuguese,23 and Spanish,24 although the latter translation is based on the Latin American style of use. The main objective of this study is to validate the translation to Spanish and its cultural adaptation to Spain. This is
justified because the lack of said adaptation could give rise to errors in its application, including diagnostic, therapy types, epidemiological records or public policies, in addition to unreliable results between studies of different authors.25
Material and methods An observational and analytic study of a cohort of patients with ocular disease. A convenience sampling was carried out in the Orduna Ophthalmologic Clinic of Madrid and in the Visión Opticians of Manresa (Barcelona). Vision-related quality of life was analyzed in the following 2 phases: - Phase 1: translation and cultural adaptation of the NEI VFQ25 questionnaire. - Phase 2: psychometric study of the reliability and validity of the scale in the European Spanish version. The study was carried out in accordance with the principles established by the Helsinki declaration and was approved by the ethics committee. The methodology applied in the study was based on the recommendations by Ramada-Rodilla et al.25 The NEI VFQ-25 questionnaire comprises a number of scores: general health (1 item), general vision (1 item), ocular pain (2 items), near vision difficulty (3 items), difficulties in far vision activities (3 items), social limitations due to vision (2 items), mental problems due to vision (4 items), role problems due to vision (2 items), dependency (3 items), difficulties
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driving vehicles (2 items), color vision problems (1 item) and peripheral vision difficulties (1 item). Each subcategory involves a score, with the final score being comprised between 0 and 100. Higher scores corresponds to better quality of life results.26,27
Phase 1 methodology. Translation and cultural adaptation The objective of the translation and adaptation to European Spanish of the NEI VFQ-25 questionnaire was to make the instrument equivalent at the semantic, conceptual, technical and approach in the Spanish language. To this end, 4 steps were followed, each based on different techniques.
Step I: direct translation A translation from English to Spanish with the involvement of 2 independent bilingual translators having European Spanish as mother tongue. One of the translators was an optician-optometrist and the other was a professional translator without previous knowledge of the questionnaire.
Step II: synthesis of translations Both translations were compared in order to identify and discuss possible discrepancies and reach an agreed-upon version.
Step III: inverse translation The agreed-upon version was again translated into English with the participation of 2 independent bilingual translators with English as mother tongue. One of the translators was a vision specialist and both did not know the original version of the questionnaire. They were requested to underline the difficulties they encountered in the course of the translation. Subsequently, both translations were analyzed to determine the existence of significant semantic or conceptual differences reaching the original questionnaire and the inversely translated versions.
Table 1 – Study patient characteristics. n = 96 Patient age, mean ± SD
71.0 ± 11.0
Sex Males, n (%) Females, n (%)
46 (47.91) 50 (52.09)
Classification based on vision VA >0.3. n (%) VA 0.3–0.1. n (%) VA <0.1. n (%) General healtha , mean ± SD General visiona , mean ± SD Ocular paina , mean ± SD Near activitiesa , mean ± SD Far activitiesa , mean ± SD Social performancea , mean ± SD Mental healtha , mean ± SD Role difficultiesa , mean ± SD Dependencya , mean ± SD Drivinga , mean ± SD Color visiona , mean ± SD Peripheral visiona , mean ± SD
66 (68.8) 20 (20.8) 10 (10.4) 48.0 ± 29.4 52.0 ± 22.9 79.6 ± 22.2 71.2 ± 30.7 72.4 ± 32.0 80.9 ± 30.0 67.2 ± 31.2 67.3 ± 37.8 76.5 ± 34.6 88.3 ± 12.6 86.6 ± 26.6 80.9 ± 29.6
a
Questionnaire score range: 0–100.
sample utilized for the validity criteria applied by the authors of the scale.28 Demographic variables (age, sex) of patients were obtained on the basis of their clinical records after obtaining their authorization and signature of informed consents. Visual acuity (VA) was analyzed, classifying the sample in 3 groups based on the definition of poor vision (binocular VA with best offsetting) and legal blindness (binocular VA with best offsetting <0.1). The NEI VFQ-25 questionnaire was given to the patients for filling in and subsequent study.
Statistical analysis Step IV: consultation by an expert committee A committee with 3 vision experts, a methodologist and the translators was established with the aim of obtaining a consolidated questionnaire adapted to European Spanish. The committee had the direct translations (step 1), the summarized version (step 2) and the inverse translations (step 3) and discussed the discrepancies that were identified. Special attention was given to any difficulty in the understanding of the questions.
Phase II methodology: psychometric reliability and validity study The individuals who took part in the study were over 21 years of age, having Spanish as mother tongue and had the ability to respond to a questionnaire filling in answers to questions and having one of the following ocular conditions: AMD, diabetic retinopathy, open angle primary glaucoma or retinitis due to cytomegalovirus, or with poor vision without a diagnosed cause. A convenience sampling was selected to assess the psychometric properties of the instrument until a size of 96 patients was reached. The objective of the sample was to replicate the
Descriptive statistics of the analyzed variables were carried out, expressing said variables as mean ± standard deviation (SD) or median (interquartile range) based on the parametric performance thereof. For qualitative variables, absolute (n) and relative (%) frequencies were utilized. Questionnaire reliability was analyzed by means of internal consistency. Validity analysis took into account the validity of the contents and the construct. Statistical analyses were carried out with the SPSS application (version 21.0; IBM Corp, Armonk, NY, USA).
Results Table 1 describes the demographic and clinical characteristics of the 96 patients who completed to be NEI VFQ-25 questionnaire in its European Spanish version as well as the score obtained in each item evaluated therein. The mean age of patients was 71.0 ± 11.0 years, with similar distribution between 47.91% of males and 52.09% of females. For scorings based on vision, nearly 70% with very good vision was obtained. The study subjects produced a general
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Table 2 – Subscale reliability analysis.
General health General vision Ocular pain Near activities Far activities Social performance Mental health Role difficulties Dependency Driving Color vision Peripheral vision
Assessable cases (n)
Scorea (mean ± SD)
Cronbach alpha (CI 95%)
96 96 96 96 96 96 96 96 96 38 96 96
48.00 52.00 79.58 71.16 72.40 80.94 67.20 67.25 76.54 88.27 86.63 80.94
± ± ± ± ± ± ± ± ± ± ± ±
NA NA 0.769 (0.654–0.845) 0.926 (0.896–0.948) 0.913 (0.877–0.940) 0.906 (0.861–0.937) 0.868 (0.819–0.906) 0.949 (0.924–0.966) 0.937 (0.911–0.956) 0.594 (0.299–0.777) NA NA
29.45 22.92 22.20 30.71 31.98 29.98 31.24 37.81 34.64 12.63 26.59 29.61
NA: could not be assessed due to having only one item. a
Questionnaire score range: 0–100. Analysis of main components Sedimentation Graph Extraction
4.5 General health
0,697
General vision
0,656
Ocular pain
0,583
Near activities
0,785
Far activities
0,883
Social performance
0,699
Mental health
0,833
Role difficulties
0,910
Dependency
0,851
1.0
Driving
0,650
0.5
Color vision
0,809
Peripheral vision
0,759
4.0
Autovalues
3.5 3.0 2.5 2.0 1.5
0.0 1
2
3
4
5
6
7
8
9
10 11 12
Component number
Fig. 1 – Sedimentation graph with analysis of main components.
health score below 50 points and in the area of 52 for general vision. As can be seen in Table 1, the scores obtained for the rest of items were close to 70 or greater, the highest being for driving (Table 1).
In general, it was observed that the scores for the general health and vision items were the lowest, in the area of 50 points. In contrast, the rest of items obtained scores close to or even above 70 points (Table 2).
Validity Reliability Overall, 96 questionnaires were analyzed. NEI VFQ-25 (European Spanish version) reliability, calculated on the basis of the Cronbach alpha coefficient for all 12 items, was 0.831 (CI 95%: 0.735–0.904). The elimination of none of the items produced an increase of over 0.10 points compared to the global coefficient. The corrected element-total correlations did not exhibit negative values and, out of the 10 questions having a value under 0.30; only question 3 was under 0.22. Reliability analysis for subscales (Table 2) showed homogeneity with values above Cronbach alpha 0.7 in all cases with the exception of driving that achieved a value of 0.594. This value matched the results obtained in other studies carried out with the original version because the question concerns an activity that can be carried out adequately or not at all and obtained only 38 responses, well below the 96 responses obtained for the rest of items. This explains its lower value.
The Kaiser Meyer Olkim test, obtained from the analyzed questionnaires, showed a value of 0.674, indicating that the ratio between items was lower. Even so, Bartlett’s sphericity test provided a value of p < 0.001, which means that the factorial analysis was adequate despite the presence of many subscales that are not adequately represented in the factorial solution (general health and vision, ocular pain and driving). Fig. 1 shows the analysis of the main components together with the sedimentation graph where it can be appreciated that the first 4 items collect almost 76% of aggregate variability (Fig. 1). Table 3 shows the difference between the various groups, classified on the basis of VA: - Best corrected binocular VA >0.3. - Best corrected binocular VA 0.3–0.1. - Best corrected binocular VA <0.1.
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Table 3 – Comparison of variables based on a visual acuity. VA >0.3 N = 66 General healtha General visiona Ocular paina Near activitiesa Far activitiesa Social performancea Mental healtha Role difficultiesa Dependencya Drivinga Color visiona a
52.60 59.41 86.05 82.36 84.72 93.11 80.25 92.21 87.61 95.65 88.04
± ± ± ± ± ± ± ± ± ± ±
29.00 20.72 17.00 22.12 21.66 13.81 21.40 18.020 12.65 14.19 22.93
VA 0.3–0.1 N = 20
VA <0.1 N = 10
35.0 ± 23.5 37.0 ± 16.26 69.38 ± 26.12 56.87 ± 7.95 55.00 ± 31.19 63.75 ± 3315 43.43 ± 31.57 52.50 ± 36.38 – 77.50 ± 34.31 77.50 ± 31.30
40.00 32.00 55.00 23.33 22.50 30.00 30.00 20.83 – 45.00 42.50
± ± ± ± ± ± ± ±
p value
37.6 25.30 23.71 3.38 31.19 30.16 31.70 33.61
± 30.73 ± 35.45
0.026 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 – <0.01 <0.01
Questionnaire score range: 0–100.
It can be seen that, as expected, the score for all questionnaire items was higher in patients having better vision. Accordingly, patients having better vision have a higher quality of life score (Table 3).
Discussion The translation of the NEI VFQ-25 questionnaire to Spanish and specific cultural adaptation to Spain has become a pioneering initiative in our country. This will avoid problems in the understanding of the questionnaire and obtain more objective and reliable data to improve the follow-up of the quality of life of patients affected with diseases such as AMD, diabetic retinopathy, open angle primary glaucoma or retinitis due to cytomegalovirus or with poor vision without a diagnosed cause. The reliability and validity results show that said translation and cultural adaptation fulfills expected requirements and was well accepted by users. When compared with the original questionnaire28 the results are similar and comparable, and accordingly it can be stated that its utilization in daily clinic practice in Spain is justified as an easy and validated method to determine the quality of life of patients and follow-up any changes therein regardless of the results obtained in other objective questionnaires. This is essential for some degenerative diseases such as AMD which is increasingly predominant in the population. Comparing each item with the Latin American Spanish translation24 it can be seen that some questions that gave rise to doubts in the previous translation are much clearer in the version developed by this study. In fact, cultural adaptation and translation to Spanish has provided a clear and objective tool to measure quality of life changes in patients who, even though were not able to improve their visual acuity, have improved in carrying out daily life activities related to vision.
Conflict of interests The authors state the absence of any potential conflict of interests related to this article.
Acknowledgments The authors wish to express their gratitude to Dr. Pablo Gili for his support in the early stages of this study and to Professor David Sanz Rosa of the European University for generously contributing his time and judgment during the development of the questionnaire.
Appendix A. Supplementary data Supplementary data associated with this article can be found in the online version at doi:10.1016/j.oftale.2018.09.001.
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