Visual acuity measurements in a national sample of British elderly people

Background—Despite the fact that visual function has an important role in the quality of life in later years, very few studies have measured visual acuity in population based nationwide samples of British elderly people. Such measurements were carried out in the context of the national diet and nutrition survey of people aged 65 years or over (NDNS). Methods—NDNS participants, who were living in 80 diVerent randomly selected postcode areas of mainland Britain, were visited at their home by a nurse who measured visual acuity at 3 metres, using the Glasgow acuity card (GAC) method. In addition, a brief questionnaire related to ocular health was administered. Results—Visual acuity was measured in 1362 NDNS participants who were not classified as mentally impaired. Visual impairment (using the WHO low vision criteria) was measured in 195 (14.3%) subjects. Prevalence of visual impairment increased significantly with age (65–74 years 3.1%; 75–84 years 11.6%; 85+ years 35.5%, p<0.001 for trend). Impaired vision was more common in subjects living in a nursing home (odds ratio adjusted for age 2.59 (95% CI 2.23 to 2.96)) and in women (odds ratio adjusted for age 1.55 (95% CI 1.21 to 1.89)). 132 (9.7%) subjects had previously undergone cataract surgery and another 157 (11.5%) had been told that they currently had cataract. Vision improved 0.2 log units or more (at least one Snellen line) with the aid of a pinhole occluder in 289 subjects (21.2%). Conclusion—Results of this nationwide, community based study confirm that problems with poor distance visual acuity exist in a substantial part of the elderly community, particularly in women and people living in nursing homes. (Br J Ophthalmol 2000;84:165–170) Although visual function is known to have an important role in the quality of life in elderly populations, very few studies have measured visual acuity in representative population based samples of British elderly people. Moreover, housebound elderly and people living in nursing homes have not been included in most studies. Prevalence data of visual impairment are extremely important for the adequate planning of services for this age group. A unique opportunity to study visual acuity in a nationwide random sample of British elderly people arose in the context of the national diet and nutrition survey of people aged 65 years or over. Because measurements were carried out at the subject’s home and in nursing homes, frail and immobile people could also be included in the study. This paper presents the prevalence of visual impairment in survey participants and evaluates the feasibility of the Glasgow acuity card method in a community based study of visual acuity.