Vision Loss and Dementia: Is There a Link?



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New study examines links between eye health and dementia risk. Joanne Temple / EyeEm / Getty Images
  • Several systemic conditions – conditions that affect the whole body – are modifiable risk factors for dementia.
  • Certain types of visual impairment can be early indicators of dementia.
  • When systemic conditions combine with visual impairment, the risk of dementia is significantly higher.

There is currently no effective treatment to stop the progression of dementia. Therefore, it is important to identify risk factors, especially those that are modifiable, to help control and eventual prevention of this pandemic.

A recent study, published in the British Journal of Ophthalmology, examines ophthalmic and systemic conditions and their relationship to dementia.

Numerous studies have identified that systemic conditions, such as obesity, depression, hypertension, and diabetes, are main risk factors for dementia.

On the other hand, studies examining a possible relationship between visual impairment and dementia or cognitive impairment are inconsistent and limited by small sample sizes.

Ophthalmic and connective tissue disorders often occur simultaneouslybecause they are all related to increasing age. However, it is not clear whether these ophthalmic conditions are independently associated with a higher risk of dementia.

The authors of the recent study analyzed data from the British Biobank To determine whether ophthalmic conditions alone – in the absence of other high-risk systemic conditions – are indicators of a higher incidence of dementia.

For the study, the researchers evaluated 12,364 adults aged 55 to 73 between 2005 and 2010, then followed them for 11 years until 2021. During that time, they recorded 2,304 cases of all-cause dementia as well. as 945 cases of Alzheimer’s disease and 513 cases of vascular dementia.

Scientists asked these participants if a doctor told them during the study period that they had certain common medical conditions. These conditions included heart disease, stroke, high blood pressure, depression, and diabetes.

Analysis of the data showed that stroke only, heart disease only, diabetes only, hypertension only, and depression only were independently linked to an increased risk of dementia.

In combination with any of these conditions, age-related macular degeneration was also associated with an increased risk of dementia.

This combined risk was greater than for people with macular degeneration only or only the systemic disease.

Compared with participants who did not have an eye problem at the start of the study, the risk of dementia was 26% higher in those who developed age-related macular degeneration during the study period. .

Participants with cataracts showed an 11% increased risk, and those with diabetes-related eye disease were 61% more likely to have dementia.

Glaucoma was not associated with an increased risk of Alzheimer’s disease or all-cause dementia. However, the condition indicated a higher risk of vascular dementia. The authors noted that when glaucoma was associated with stroke, heart disease, diabetes, hypertension, or depression, the risk of all-cause dementia increased significantly.

The reason for an apparent association between ophthalmic conditions and dementia is unknown, but the authors list several possibilities.

Ophthalmic conditions often coexist with well-known systemic risk factors for dementia. They are also often present in the elderly, those who smoke and are less physically active, and those who have a low level of education.

In particular, visual impairment can be one of the first manifestations of dementia. Reduced stimulation of the visual sensory pathways can lead to an acceleration of its progression.

Dr Richard Rosen, a vitreoretinal surgeon at Mount Sinai Medical Center in New York City and vice president and director of ophthalmology research, said Medical News Today that this study reinforces the fact that healthcare professionals must be on the lookout for these risk factors.

“People who have these risk factors should be monitored,” Dr. Rosen said. He pointed out that there are new approaches that could control the progression of dementia and possibly prevent the disease.

“More research is needed in various populations to compare eye conditions and the risk of dementia,” said Claire Sexton, Doctor of Philosophy, director of scientific programs and awareness of the Alzheimer’s Association, in an interview with MNT.

She also pointed out that more research is needed to determine whether correcting vision loss can reduce the risk of cognitive decline.

“Bottom line for individuals is: if you are suffering from vision loss, it is important to see an ophthalmologist to explore options for vision correction,” Sexton said.

While the study population was particularly large and covered a significant period of time, the authors note that this was an observational study only and does not indicate causation. They also mention several other limitations.

For example, the authors explain that many of the eye conditions have been self-reported. In addition, some of the reported cases of dementia may have occurred before the eye disease.

The authors conclude that age-related macular degeneration, cataracts, and diabetes-related eye disease, but not glaucoma, are associated with an increased risk of dementia.

People who have both ophthalmic and systemic conditions are at even higher risk than those with only an ophthalmic condition or a systemic condition only.



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