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Clinical science
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The development of the Indian vision function questionnaire: field testing and psychometric evaluation
  1. S K Gupta1,
  2. K Viswanath2,
  3. R D Thulasiraj3,
  4. G V S Murthy1,
  5. D L Lamping4,
  6. S C Smith4,
  7. M Donoghue4,
  8. A E Fletcher4
  1. 1Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
  2. 2Sarojini Devi Eye Hospital, Hyderabad, India
  3. 3Lions Aravind Institute of Community Ophthalmology, Madurai, India
  4. 4London School of Hygiene and Tropical Medicine, London, UK
  1. Correspondence to: Professor Astrid E Fletcher Department of Epidemiology and Population Health, Keppel Street, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK; astrid.fletcherlshtm.ac.uk

Abstract

Objective: To develop and evaluate the acceptability, reliability, validity, and responsiveness of the Indian vision function questionnaire (IND-VFQ).

Methods: Problem statements from previous qualitative studies were reduced to a 45 item interviewer administered questionnaire representing three a priori domains (general functioning, psychosocial impact, and visual symptoms) which was evaluated in patients with cataract (n = 420), glaucoma (n = 120), diabetic retinopathy, or age related macular degeneration (n = 120) and normal controls (n = 120). Standard methods were used for item reduction and to evaluate psychometric properties.

Results: Psychometric item reduction produced a 33 item questionnaire. Psychometric evaluation showed that two of the three scales (psychosocial impact and visual symptoms) had good acceptability, and that all three scales showed high internal consistency (alpha >0.80; item-total correlations 0.54–0.86) and test-retest reliability (>0.89). All three scales showed moderate evidence of convergent and discriminant validity. Responsiveness, assessed in cataract patients (n = 120) before and after surgery, was good for all three scales (effect sizes >1).

Conclusions: The IND-VFQ33 is a psychometrically sound measure of vision function addressing a gap in patient defined measures of vision function developed in populations living in low income countries.

  • IND-VFQ, Indian vision function questionnaire
  • vision function questionnaire
  • psychometric evaluation
  • blind
  • visually impaired
  • low income countries
  • IND-VFQ, Indian vision function questionnaire
  • vision function questionnaire
  • psychometric evaluation
  • blind
  • visually impaired
  • low income countries

https://doi.org/10.1136/bjo.2004.050732

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    Footnotes

    • This study was funded by the US-India Fund via the US Embassy, New Delhi, India.

    • Data access and responsibility: Drs GVS Murthy and Dr SK Gupta had full access to all the data in the study and take responsibility for the integrity of the data and the data analysis.

    • Study staff at each centre: Dr Rajendra Prasad Centre for Ophthalmic Sciences: Professor HK Tewari, Professor VK Dada (Emeritus), Dr Lalit Sanga, Zakia Sultan, Akhilesh Kumar, Kiran Singh, Neena John, Hira Ballabh Pant, KG Varghese, Priska Kujur, Naveen Bhatt, RP Pathak, Rakesh Tewari, and Kamal Kishor: Aravind Eye Hospital: Dr Dipankar Dutta, Preethi Pradhan, V Vijaykumar, R Janakeeswari, Ms Manimeghalai: Sarojini Devi Eye Hospital: Dr R Praveen Krishna, D Sunitha Bhat, S Anitha, K Bala Saraswathi Kumari, Mr Ramesh, Kiran Didugu.

    • The technical advisory committee: Dr Leon B Ellwein (Committee Chair), Associate Director, National Eye Institute, National Institutes of Health, Building 31, Room 6A51, 31 Center Drive, Bethesda, MD, USA; Dr Damodar Bachani, Assistant Director General (Ophthalmology), Directorate General of Health Services, Government of India, New Delhi; Dr Paul Lee, Professor of Ophthalmology, Duke University Medical Centre, USA; Dr Carol Mangione, Professor of Medicine, David Geffen School of Medicine UCLA, Los Angeles, USA; Dr Rhett Schiffman, former director of uveitis services and clinical research, Henry Ford Health Systems, Detroit, USA (currently at Allergan, Inc).