Another very important reason to take care of your eyes

(SOUTH YARMOUTH) – Good eyesight is precious for many reasons, and now researchers have found another very important one – lowering dementia risk.

A recent analysis of medical records of more than 3,000 people 65 or older who had surgery for glaucoma or cataracts found those that underwent cataract surgery experienced about a 30 percent reduction of risk of developing dementia. This effect remained strong for the first five years after cataract surgery, declining afterward, but still significant for more than 10 years.

The study included information from glaucoma patients as a control group, as cataract surgery restores vision, while glaucoma surgery does not, though it can stop the condition from getting worse. Researchers did not find a similar risk reduction of dementia from glaucoma surgery.

Poor vision can contribute to loss of brain skills, said Hyannis neurologist Sean P. Horrigan, DO. Many neurologists, gerontologists and other health experts know from their work that vision loss can precipitate the onset of dementia or hasten its progression, he said.

“I think we all know it’s an important factor,” he said.

Your eyes might almost be considered an extension of your brain. Of all the senses, only vision has an entire lobe of the brain dedicated to it – the occipital lobe at the back of the skull, noted Dr. Horrigan.

The analysis was done by researchers in Seattle, WA, and utilized data from the “Adult Changes in Thought” study, a long-term project conducted by the Kaiser Permanente Washing Research Institute and the University of Washington. Study results were published December 6, 2021 in JAMA Internal Medicine.

Well-functioning senses, especially sight and hearing, help keep our minds stimulated and the loss of these can lead to social isolation and declines in activity, contributing to mental decline, wrote the researchers of the Washington analysis. Earlier studies of procedures to improve hearing or vision deficits and their effect on dementia risk have produced mixed results, however, they used lower-quality data or didn’t consider other potential factors, the researchers wrote.

The Washington study examined several factors – amount of education, sex, race, history of smoking, and presence of an APOE e4 allele – and only not having the allele was associated with a higher reduced risk of dementia than cataract surgery. This allele, or version, of the APOE gene, is associated with a greater chance of developing late-onset Alzheimer’s disease, though not all people with the allele get Alzheimer’s, nor do all Alzheimer’s patients carry the allele, according to the National Library of Medicine.

For all forms of dementia, including Alzheimer’s disease, the reduction associated with cataract surgery was 32 percent within the first five years, and 24 percent afterward. For only Alzheimer’s disease, the reduction was 35 percent for the first five years after surgery, and 19 percent afterward.

“Your brain performance is always going to be at its best when your eyes and other senses are at good performance,” Dr. Horrigan said.

“When individuals get the best eye care, or get hearing aids, they’re more social, more cognitively active,” he continued.

Dr. Horrigan said about half of his patients have Alzheimer’s disease or another type of dementia. He recommends older adults have their hearing and vision checked regularly. “I would recommend getting an eye exam at least every other year,” he said.

To reduce your chances of developing dementia, Dr. Horrigan also suggests:

• Avoid drinking alcohol and smoking
• Eat a healthy diet and exercise regularly
• Maintain good sleep habits.

By Rich Holmes, Cape Cod Health News