Objective: To study the prevalence and distribution of visual impairment and eye diseases by age and gender in an urban institutionalized population.
Design: Cross-sectional study.
Participants: Four hundred three residents of nursing homes and hostels.
Methods: Fourteen nursing homes were randomly selected from 104 nursing homes and hostels located within a 5-km radius of each of nine clusters studied in the Visual Impairment Project (VIP) urban cohort. Participants completed a standardized orthoptic and dilated ophthalmic examination, including measurement of visual acuity and visual fields. The major cause of vision loss was identified for participants with visual impairment.
Main outcome measures: Presenting visual acuity and ophthalmic diagnoses.
Results: The participants' mean age was 82 years (standard deviation, 9.24), with an age range of 46 years to 101 years. Women outnumbered men by 318 to 85. Seventy-one (22%) of 318 women had bilateral profound visual impairment (blindness), defined as best-corrected visual acuity <3/60 and/or visual field constriction <5 degrees compared with 10 (12%) of 85 men. However, this difference is not significant when age-standardized. Age-related macular degeneration was the principal diagnosis of vision loss in the better eye of 74 (44%) of the 167 participants with bilateral low vision (<6/18 and/or visual field constriction to <20 degrees radius). The age-adjusted rate of blindness or profound visual impairment in the VIP institutional cohort of 5.2% (95% confidence interval [CI], 1.8, 8.6) was significantly greater than in the VIP urban and rural cohorts of 0.13% (95% CI, 0, 0.25) and 0.29% (95% CI, 0, 0.57), respectively.
Conclusions: Underestimation of visual impairment may occur in residential population-based studies that exclude institutional or residential nursing homes and hostels for the aged citizens. Expanded methods are required for visual assessment in institutional populations.