Visual impairment from cataract and health related quality of life: results from a case-control study in the Philippines.

PURPOSE: To evaluate a vision related quality of life (VRQoL) scale, the World Health Organization Prevention of Blindness and Deafness Visual Function-20 (WHO/ PBD VF20) and describe the relationship between visual impairment from cataract and vision related and generic Health Related Quality of Life (HRQoL) in a case-control study of adults aged > or = 50 years in the Philippines. METHODS: Two hundred and thirty eight population based persons visually impaired from cataract and 163 age- gender- matched controls with normal vision were interviewed using the WHO/PBD VF20 and European Quality of Life (EuroQol) questionnaire (an HRQoL). The WHO/PBD VF20 was evaluated using standard psychometric tests. RESULTS: The WHO/PBD VF20 had good item acceptability and validity. Cases had significantly poorer VRQoL than controls and worsening Visual Acuity (VA) was associated with worsening VRQoL. The general functioning subscale had good internal consistency. The psychosocial sub-scale had a Cronbach's alpha of 0.61, just below the generally accepted criteria of 0.70. Cases were much more likely than controls to report problems with the Euroqol five descriptive domains (EQ-5D)and had significantly poorer self-rated health. CONCLUSIONS: The study supports the use of the WHO/PBD VF20 in a Philippine population and highlights the worsening VRQoL associated with cataract vision loss. The poorer generic HRQoL among cases compared to controls indicates an impact of visual impairment on perceived health and well-being, beyond vision-specific experience.