Abstract
Purpose: :
To compare cross–sectional and longitudinal results from a large battery of vision functions measured in a sample of elderly community living participants living in Marin County, CA in order to determine whether the survivors have better vision function than those lost to follow–up or death.
Methods: :
Vision function was assessed in a sample of 900 participants using an extensive battery of vision functions. 306 participants (mean age 78.7 years; 59–101 years) were tested only once and 452 participants (mean age at baseline 72.9 years; 58–102 years) were tested 3 times over an average period of 7.0 years (range 4.9–9.2 years). The test battery consisted of spatial vision measures (high and low contrast acuity, contrast sensitivity, disability glare and low contrast low luminance acuity), color vision, visual fields with and without an attentional component and stereopsis. Observers were tested binocularly with habitual correction under standardized conditions.
Results: :
The vision function versus age for the cross–sectional sample (N=306) and the longitudinal sample (N=452) were similar for all of the vision measures. All spatial vision measures were on average slightly (0.15–0.25 log units) worse in those tested only once. However, the 306 participants tested only once were older, less educated and had more medical conditions than those followed longitudinally. These small differences remained statistically significant when controlling for age, gender, years of education and number of medical conditions (analysis of covariance). Each vision function demonstrates a unique change with age in the longitudinal sample similar to the cross–sectional results for the entire sample of 900 published previously. Of all the spatial vision measures, standard high contrast visual acuity shows the smallest change with age while disability glare and low contrast low luminance acuity show the most dramatic losses with increasing age.
Conclusions: :
The cross–sectional and longitudinal results are remarkably similar across all vision functions even though small but statistically significant differences exist with the longitudinal sample showing slightly better vision function.
Keywords: aging: visual performance • visual acuity • clinical (human) or epidemiologic studies: natural history