Relationship between visual impairment and eye diseases and visual function in Andhra Pradesh.

OBJECTIVE: To determine the impact of visual impairment and eye diseases on visual function in an older population of Andhra Pradesh in southern India.

DESIGN: Population-based cross-sectional study.

PARTICIPANTS: The visual function questionnaire (VFQ) was completed by 7363 (99.1% of the 7431 eligible) persons aged 16 years or older participating in the Andhra Pradesh Eye Disease Study identified from 70 clusters in 3 rural areas and 24 clusters in 1 urban area. Participants aged 40 years or older (n = 3676), 98.7% of the 3724 eligible, who underwent an interview and a detailed dilated ocular eye evaluation by trained professionals were included in this study.

METHODS: The psychometric properties of the VFQ were evaluated among visually impaired persons. The authors examined the relationships of overall visual function score with presenting visual acuity in the better eye, specific eye diseases, and demographic variables.

MAIN OUTCOME MEASURE: Visual function score.

RESULTS: Internal consistency was high for the entire questionnaire (Cronbach's alpha, 0.92). All the items of the visual function scale had an adequate item-total correlation (range, 0.44-0.75) of more than 0.2. After adjusting for demographic variables and ocular disease, persons with visual impairment had significantly lower scores of functional vision. Persons with glaucoma, corneal disease, or retinal disease independent of visual acuity had lower scores compared with persons without these eye diseases. Persons with cataract had significantly lower scores than those without cataract in the model without visual acuity, but did not have significantly lower scores when visual acuity was added to the model.

CONCLUSIONS: The VFQ may be used as a measure of functional vision across a range of visual problems among older adults in Andhra Pradesh. Presenting visual acuity in the better eye was associated with functional vision in this population. Decrease in functional vision was associated with the presence of glaucoma, corneal disease, or retinal disease independent of visual acuity, and with cataract as a function of visual acuity.