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Cataract visual impairment and quality of life in a Kenyan population
  1. Sarah Polack1,
  2. Hannah Kuper1,
  3. Wanjiku Mathenge2,
  4. Astrid Fletcher1,
  5. Allen Foster1
  1. 1London School of Hygiene & Tropical Medicine, London, UK
  2. 2Rift Valley Provincial General Hospital, Nakuru Town, Nakuru, Kenya
  1. Correspondence to: S Polack London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, UK; sarah.polack{at}


Aims: To evaluate the World Health Organization Prevention of Blindness and Deafness 20-item Visual Functioning Questionnaire (WHO/PBD VF20), a vision-related quality of life scale, and to describe the relationship between cataract visual impairment and vision- and generic health-related quality of life, in people ⩾50 years of age in Nakuru district, Kenya.

Methods: The WHO/PBD VF20 was pilot tested and modified. 196 patients with visual impairment from cataract and 128 population-based controls without visual impairment from cataract were identified through a district-wide survey. Additional cases were identified through case finding. Vision- and health-related quality of life were assessed using the WHO/PBD VF20 scale and EuroQol generic health index (European Quality of Life Questionnaire (EQ-5D)), respectively. WHO/PBD VF20 was evaluated using standard psychometric tests, including factor analysis to determine item grouping for summary scores.

Results: The modified WHO/PBD VF20 demonstrated good psychometric properties. Two subscales (general functioning and psychosocial) and one overall eyesight-rating item were appropriate for these data. Increased severity of visual impairment in cases was associated with worsening general functioning, psychosocial and overall eyesight scores (p for trend <0.001). Cases were more likely to report problems with EQ-5D descriptive dimensions than controls (p<0.001), and, among cases, increased severity of visual impairment was associated with worsening self-rated health score.

Conclusion: The modified WHO/PBD VF20 is a valid and reliable scale to assess vision-related quality of life associated with cataract visual impairment in this Kenyan population. The association between health-related quality of life and visual impairment reflects the wider implications of cataract for health and well-being, beyond visual acuity alone.

  • EQ-5D, European Quality of Life Questionnaire
  • EuroQol, European quality of life
  • HRQOL, health-related quality of life
  • INDVFQ33, Indian VF33 questionnaire
  • PCA, principal components analysis
  • QOL, quality of life
  • SES, socioeconomic status
  • VA, visual acuity
  • VAS, visual analogue scale
  • VF, vision function
  • VRQOL, vision-related quality of life
  • WHO/PBD VFQ20, World Health Organization Prevention of Blindness and Deafness 20-item Visual Functioning Questionnaire

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  • Published Online First 31 January 2007

  • Funding: This study was funded by grants from Sight Savers International, Christian Blind Mission and ORBIS International.

  • Competing interests: None.