posted on 9/14/2021 06:00
Patient undergoes eye exam: study associates disability with cognitive degradation – (credit: Lucy Nicholson/Reuters – 9/27/12)
Age-related macular degeneration, cataracts and diabetes-related eye diseases are associated with an increased risk of dementia, says research published in the British Journal of Ophthalmology. According to the authors, visual impairment may be one of the first signs of cognitive degradation, and reduced stimulation of visual sensory pathways is believed to accelerate its progression.
A few small studies have suggested that this relationship may exist. The incidence of ophthalmic diseases increases with age, as does that of chronic and systemic diseases such as diabetes, hypertension, depression, heart disease and stroke, which are accepted risk factors for dementia. Therefore, it is unclear whether these eye conditions are associated with an increased risk of dementia.
For the study, the authors analyzed data from 12,364 adults aged 55-73 years. Participants were evaluated between 2006 and 2010 and monitored until early 2021. Data analysis showed that age-related macular degeneration, cataracts, and diabetes-related eye disease were independently associated with increased risk of cognitive decline.
Compared with people who did not have eye disease at baseline, the risk of dementia was 26% higher in those with age-related macular degeneration, 11% higher in those with cataracts, and 61% higher in those with diabetes. Although glaucoma was not associated with an increased risk of Alzheimer’s disease, the authors found a relationship with vascular dementia.
As this is an observational study, a cause and effect relationship cannot be established. However, the authors conclude in the article: “Age-related macular degeneration, cataracts, and diabetes-related eye diseases, but not glaucoma, are associated with an increased risk of dementia. Individuals with ophthalmic and systemic diseases are at higher risk of dementia compared to those with ophthalmic or systemic diseases only. Hypertension, diabetes, stroke, heart disease, and newly developed depression mediated the association between cataract/diabetes-related eye diseases and dementia.”