Longitudinal studies of vision in older people

Visual acuity was measured an cataract recorded in a simple random sample of 215 men and 272 women aged 63-90 years in Edinburgh. One year and five years later the observations were repeated in 113 men and 148 women surviving and available from the original sample. This paper deals with survivors only. Worsening of visual acuity occurred over five years in 12% of men and 14% of women. Improvement was noted in 15% of men and 10% of women. The proportion of those with worsening of visual acuity increased significantly with increasing age at entry to the study. Assessments made by subjects of visual change in five years proved inaccurate when checked by measurement. Prevalence of cataract rose from 15% at the original examination to between 36% and 46% after five years. Increases in prevalence of cataract were greated in older subjects. If cataract was present at any examination, visual acuity worsened in five years in 24% of subjects compared with 11% without cataract at any examination. The proportion of persons with cataract and vision worse than 6/12 was 76% of 37 persons at the original examination and 66% of 105 after five years. Corresponding figures in those without cataract were 37% of 223 and 36% of 155. The actual number with poorer vision associated with cataract more than doubled in five years.