Study claims cataract eye surgery can lower dementia risk significantly

By Georgia Lambert via SWNS

Undergoing eye surgery to treat cataracts lowers the risk of dementia by 30 percent, according to new research.

Cataracts affect most older adults at risk of developing dementia, but researchers have now found strong evidence that undergoing cataract surgery is linked with a lower risk of developing dementia.

Using a long-standing, observational study called the Adult Changes in Thought (ACT), researchers from the Kaiser Permanente Washington, enlisted the help of over 5,000 participants who were older than 65 years old.

After analyzing the data of over 3,000 participants, they found that people who had undergone this type of surgery had nearly a 30 percent lower risk of developing dementia from any cause compared with those who did not.

What is more, this lowered risk persisted for at least a decade after surgery and this specific treatment was also linked with a lower risk of Alzheimer's disease.

“This kind of evidence is as good as it gets in epidemiology," saidDr. Cecilia Lee, an associate professor, the study's lead researcher and Klorfine Family Endowed Chair in ophthalmology at the University of Washington School of Medicine.

“This is really exciting because no other medical intervention has shown such a strong association with lessening dementia risk in older individuals.”

The ways in which cataract surgery lessened the risk of dementia was not found in this study, however, the researchers believe that people may be getting "higher quality sensory input" after cataract surgery, which might be beneficial in the fight against developing dementia.

Dr. Eric Larson, a principal investigator of the ACT study and its co-author, is also a senior investigator at Kaiser's Health Research Institute.

“These results are consistent with the notion that sensory input to the brain is important to brain health," he said.

Lee went on to explain that another potential explanation is that after the surgery, people are getting more blue light.

“Some special cells in the retina are associated with cognition and regulate sleep cycles, and these cells respond well to blue light," she said.

“Cataracts specifically block blue light, and cataract surgery could reactivate those cells.”

The study results drive a strong case for further research to be carried out on the eye-brain connection in dementia.

Previous studies by Lee and her team have shown a strong link between other retinal diseases, such as age-related macular degeneration of the retina, and the development of Alzheimer's disease and dementia.

Patients suffering from macular degeneration or other retinal degenerative diseases are more likely to develop dementia.

In the current study, the participants who underwent vision-improving cataract surgery had a lower risk of developing dementia.

For this field of research to progress, further understanding is needed into the connection between the aging eye and brain, and these findings may offer insights and potential therapies to slow or prevent age-related dementia.

To reach this breakthrough, the researchers tracked participants who were diagnosed with a cataract or glaucoma but who did not have dementia at the time they volunteered for the study.

The participants also hadn't undergone a cataract surgery at their time of enrollment.

They were then evaluated every two years and their cognitive abilities were measured using an instrument that scored them in a range from zero to 100.

The participants who scored less than 85, were sent for more neurological tests.

During a follow-up of 3,038 patients, 853 developed dementia, with 709 cases of Alzheimer's disease.

For half of the participants who had undergone cataract surgery in either eye, these lucky people were about 30 percent less likely to develop any form of dementia for at least ten years after their surgery.

The researchers factored in a huge range of variables, such as excluding those who had undergone surgeries in the two years before their dementia diagnosis.

They did this to rule out the possibility that people with cognitive decline prior to their diagnosis may have been less conscious of vision issues and then less likely to have sought out surgical treatments.

Even by excluding this group, the researchers found lower risks of dementia associated with cataract surgery.

In light of Lee's research, Dr. Howard Fillit, the founding executive director and chief science officer of the Alzheimer's Drug Discover Foundation (ADDF), said: “Innovative research like Dr. Lee’s is helping to uncover how age-related changes in our senses contribute to dementia."

The ADDF - a nonprofit that accelerates the discovery and development of drugs to treat and prevent Alzheimer’s disease and related dementias, has supported Lee's work to develop new diagnostic tools for Alzheimer's that use non-invasive imaging of the retina and artificial intelligence.

The study's findings were reported in the JAMA Internal Medicine journal.