Creation and testing of a practical visual function assessment for use in Africa: correlation with visual acuity, contrast sensitivity, and near vision in Malawian adults
- Karin van Dijka,
- Susan Lewallenb,
- Moses Chiramboc,
- Jane Gardinerb,
- Brian Hoarb,
- Janette Lindleyb,
- N Kevin Wadeb,
- Paul Courtrightb
- aChristoffel Blindenmission, Boshof 10, 7873 AC Odoorn, Netherlands, bBC Centre for Epidemiologic and International Ophthalmology, University of British Columbia, St Paul’s Hospital, Vancouver, Canada, cSight Savers International, PO Box 30858, Lilongwe, 3, Malawi
- Dr Paul Courtright, BC Centre for Epidemiologic and International Ophthalmology, St Paul’s Hospital, 1081 Burrard Street, Vancouver, BC V6Z 1Y6, Canada.
- Accepted 27 January 1999
Abstract
AIM To develop and test a practical visual function assessment for use in developing countries.
METHODS Using focus group discussions and interviews with eyecare workers and low vision specialists in Malawi, 13 questions related to visual characteristics of activities of daily living were designed. Patients presenting to an eye clinic were recruited and interviewed. Visual acuity, near vision, and contrast sensitivity were measured. Analysis sought to determine the degree of correlation between the vision indices and visual function.
RESULTS The visual function questionnaire was easy to administer. Visual function correlated with visual acuity, contrast sensitivity, near vision, and patient reported visual problem. People with a higher frequency of “not applicable” responses had lower visual function scores. Multivariate modelling revealed that visual acuity and number of questions felt to be applicable were independently associated with visual function. Reducing the questionnaire to nine questions did not affect the degree of correlation with any of the visual indices.
CONCLUSION The authors’ visual function assessment correlates well with different measures of visual acuity. People with reduced vision for a prolonged period may no longer consider doing certain tasks and the number of questions considered appropriate by an individual may be an additional measure of visual function. Assessment of visual function by health workers may be a valuable tool in improving surgical uptake by encouraging both health personnel and patients to recognise that they have difficulties undertaking activities of daily living as well as a measure of monitoring and evaluating cataract outcomes.
