How Vision Impairment Contributes to Dementia in Seniors

TOPLINE:

Addressing vision impairments could help with dementia prevention, as vision impairment is linked to 19% of dementia cases in older adults.

METHODOLOGY:

• Researchers conducted a cross-sectional analysis using data from the National Health and Aging Trends Study (NHATS).
• The analysis included 2767 US adults aged 71 years or older (54.7% female and 45.3% male; 8% non-Hispanic Black, 81.7% Hispanic, 81.7% non-Hispanic White, and 3.3% non-Hispanic other).
• Vision impairments were defined using 2019 World Health Organization criteria. Near and distance vision impairments were defined as greater than 0.30 logMAR, and contrast sensitivity impairment was identified by scores below 1.55 logCS.
• Dementia was classified using a standardized algorithm developed in NHATS, which incorporated a series of tests measuring cognition, memory and orientation, reports of Alzheimer’s disease, or a dementia diagnosis from the patient or a proxy, and an informant questionnaire (Ascertain Dementia-8 Dementia Screening Interview).
• The study analyzed data from 2021, with the primary outcome being the population attributable fraction (PAF) of dementia from vision impairment.

TAKEAWAY:

• The PAF of dementia associated with at least one vision impairment was 19% (95% CI, 8.2-29.7).
• Impairment in contrast sensitivity had the highest PAF among all other vision issues, at 15% (95% CI, 6.6-23.6). This figure was higher than that for impairment of near acuity, at 9.7% (95% CI, 2.6-17.0), or distance acuity, at 4.9% (95% CI, 0.1-9.9).
• The highest PAFs for dementia due to vision impairment was among participants aged 71-79 years (24.3%; 95% CI, 6.6-41.8), women (26.8%; 95% CI, 12.2-39.9), and non-Hispanic White participants (22.3%; 95% CI, 9.6-34.5).

IN PRACTICE:

“While not proving a cause-and-effect relationship, these findings support inclusion of multiple objective measures of vision impairments, including contrast sensitivity and visual acuity, to capture the total potential impact of addressing vision impairment on dementia,” study authors wrote.

SOURCE:

This study was led by Jason R. Smith, ScM, of the Department of Epidemiology at the Johns Hopkins Bloomberg School of Public Health in Baltimore. It was published online on September 5 in JAMA Ophthalmology.

LIMITATIONS:

The limited sample sizes for American Indian, Alaska Native, Asian, and Hispanic groups prevented researchers from calculating PAFs for these populations. The cross-sectional design prevented the researchers from examining the timing of vision impairment in relation to a diagnosis of dementia. The study did not explore links between other measures of vision and dementia. Those with early cognitive impairment may not have updated glasses, affecting visual performance. The findings from the study may not apply to institutionalized older adults.

DISCLOSURES:

Jennifer A. Deal, PhD, MHS, reported receiving personal fees from Frontiers in Epidemiology, Velux Stiftung, and Medical Education Speakers Network outside the submitted work. Nicholas S. Reed, AuD, PhD, reported receiving stock options from Neosensory outside the submitted work. No other disclosures were reported.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.