Longitudinal Relationships Among Visual Acuity, Functioning, and Depression: the Salisbury Eye Evaluation Study

Abstract

 

Purpose:

 

The purposes of this study were 1) to describe the visual, mental, and physical health trajectories occurring among aging adults, and 2) to estimate the relationships among the trajectories.

 

Methods:

 

A sample of 2,520 adults who were 65-84 years old in 1993-1995 and were re-assessed 2, 6, and 8 years later. Presenting acuity was assessed using an ETDRS chart, with standardized refraction testing performed on participants worse than 20/30. Activities of Daily Living (ADLs), Instrumental Activities of Daily Living (IADLs) and severe depression (based on General Health Questionnaire items) were assessed. Growth curve models were used to simultaneously estimate health trajectories (1993 values and changes over time) and obtain associations among the trajectories while controlling for relevant covariates.

 

Results:

 

Best-corrected acuity (logmar x 10) worsened by an average of 0.256 (~¼ acuity line) annually. The ADL difficulties increased by 0.38 standard deviations (SD); IADL difficulties increased by 0.49 SD (see figure). There was no annual change in severe depression. Controlling for demographic and health covariates, visual acuity declines were positively correlated with increased ADL (r = 0.17; p=0.05) and IADL difficulties (r = 0.42; p < 0.001). The direct effects of acuity loss were strongest for IADLs where a one SD decline in acuity (logmar x 10) was associated with a 0.35 SD increase in IADL difficulties (p < 0.001) at baseline and a one SD acuity decline (0.43 logmar x 10) resulted in a 0.44 SD increase in the rate of change in IADL difficulties (p < 0.001).

 

Conclusions:

 

this longitudinal study of older adults, visual acuity loss was related to increased difficulty with ADLs and especially IADLs, but was not associated with change in severe depressive symptoms. Previous cross-sectional research that examined these associations may underestimate the role that reduced vision plays in functional declines.  

 

Keywords: visual acuity • aging: visual performance