Visual Impairment, Dementia Are Detrimental to Independence of Older Adults

May 14, 2020
Patrick Campbell

New research suggests the presence of either condition can wreak havoc on an older adult's ability for movement, self-care, and household activities.

A new study from investigators at Bascom Palmer Eye Institute and Johns Hopkins University is shedding light on the impact of visual impairment and dementia can have on risk for disability in older adults.

Using data from the National Health and Aging Trends Study (NHATS), investigators found both dementia and visual impairment can have a major detrimental impact on an older person’s movement and ability to take care of themselves.

With dementia and visual impairment common issues among aging patients, investigators designed the current study as a cross-sectional analysis of NHATS data from patients 65 years of age and older. Beginning in 2011 and containing more than data on more than 7500 subjects, the NHATS offers investigators insights on a nationally representative cohort with data related to age, sex, race/ethnicity, medical comorbidities, and other factors.

As part of NHATS, subjects had their functional ability using a validated 4-level scale assesses their performance in a slew of activities pertaining to the ability for movement, self-care, and household activities. Possible score ranges were 3-12 for mobility, 4-16 for self-care, and 5-20 for household activities.

Visual impairment was self-reported and investigators considered participants visually impaired if they were blind or could not see across the street and/or read newspaper print, even with glasses on. Investigators used validated NHATS classification for determining whether or not a patient had dementia.

Using a multivariable Poisson regression, investigators sought to assess independent associations between dementia and visual impairment status on self-care, mobility, and household activity scores. Of note, multiple covariates were included in the adjusted analysis, including age in 5-year intervals, sex, race/ethnicity, highest education level, family income in quartiles, BMI, history of cataract surgery, depressive symptoms, and physician-diagnosed medical comorbidities.

Of the 7576 subjects who completed the study in 2015, 7124 were included in the investigators’ analysis. The 452 excluded were not included due to missing data for 1 or more variable, outcome, or covariate. The weighted proportion of female participants was 55.3% (95% CI, 54.0%-56.6%) and 56.1% (95% CI, 54.1%-58.1%) of participants were 65-74 years old.

The weighted proportion of participants with self-reported visual impairment was 8.6% (95% CI, 7.8%- 9.3%). In regard to dementia status, 8.3% (95% CI, 7.8%-8.9%) of participants were classified as having possible dementia and 6.3% (95% CI, 5.7%-6.9%) were considered to have probable dementia.

Upon analysis, investigators observed visual impairment was associated with a 14.7% (10.82 vs 9.23) decrease in mobility score, 9.5% (14.54 vs 13.16) decrease in self-care score, and a 15.2% (18.23 vs 15.45) decrease in household activity score compared to patients without visual impairment. Probable dementia was associated with decreases of 27.8% (10.82 vs 7.81), 22.9% (14.54 vs 11.20), and 34.7% (18.23 vs 11.90), in mobility, self-care, and household activity scores, respectively, compared to those with no dementia.

Compared to patients with no visual impairment and no dementia, experiencing both was associated with a 50.1% (10.82 vs 5.40) reduction in mobility sore, a 42.4% (14.54 vs 8.38) reduction in self-care score, and a 52.4% (18.23 vs 8.68) reduction in household activity score.

In an invited commentary, David Friedman, MD, PhD, of Massachusetts Eye and Ear Glaucoma Center of Excellence at Harvard University, and Pradeep Ramulu, MD, PhD, of the Wilmer Eye Institute Glaucoma Center of Excellence at Johns Hopkins University, highlight the impact co-occurring visual impairment and dementia can have on older patients.

“Those with VI and dementia struggle to move about freely, care for themselves, and tend to home needs; many will likely need caretakers or be forced to leave the home in which they currently live,” the pair wrote. “Understanding this, we not only ought to make greater efforts both to preserve and restore vision in these individuals but also need to identify ways in which we can ease the burden that the combination of VI and dementia can create.”

This study, “Association of Co-occurring Dementia and Self-reported Visual Impairment With Activity Limitations in Older Adults,” was published in JAMA Ophthalmology.