Cataract surgery may reduce the risk of dementia.

Over 55 million individuals Trusted Source millions of people throughout the globe suffer with dementia, an illness that involves a deterioration in cognitive abilities such as memory, language, and understanding.

Alzheimer's disease is the most prevalent kind of dementia, accounting for 60–80 percent of all dementia cases. Over the years, scientists have conducted extensive study into the origins of Alzheimer's disease; yet, the reasons remain unknown.

Researchers from the University of Washington School of Medicine in Seattle claim to have discovered a correlation between cataract surgery and a decreased chance of acquiring dementia, particularly Alzheimer's disease, in older persons.

The authors of the study feel that the enhanced sensory input and exposure to blue light following cataract surgery may help explain why. There is hope that this knowledge may lead to the development of possible new medicines to either reduce or prevent age-related dementia.

The findings of this observational study were published in the journal JAMA Internal Medicine Source.

What exactly are cataracts?

A cataract arises when proteins in the eye's typically clear lens degrade, causing it to become "cloudy."

Objects may look hazy or less vibrant when vision becomes clouded. Cataracts often begin tiny, but if left untreated, they can enlarge and impair eyesight, making reading and driving difficult.

Cataracts affect an estimated 94 million individuals worldwide, according to Trusted Source.

The most prevalent cause of cataracts is aging. Certain risk factors, including as smoking, diabetes, extensive sun exposure over a lifetime, and past eye injuries, can all increase the likelihood of getting cataracts.

Cataract surgery is the only procedure to remove a cataract. The operation entails an eye surgeon removing the normal lens of the eye and replacing it with an artificial lens known as an intraocular lens (IOL).

Aging eyes and aging brains

Dr. Cecilia S. Lee, associate professor and Klorfine Family Endowed Chair in ophthalmology at the University of Washington School of Medicine, talked with Medical News Today about the study

Previous study has established a relationship between numerous eye disorders, such as age-related macular degeneration (AMD) and diabetic retinopathy, and an increased risk of Alzheimer's disease and dementia, she noted.

"A cataract is a normal aging process of the eye that affects the majority of older persons who are at risk for dementia," noted Dr. Lee.

"The scientific community is interested in sensory loss, including vision and hearing, as a possibly modifiable risk factor for dementia." We anticipated that because cataract surgery improves visual function, elderly adults who get it may have a lower chance of acquiring Alzheimer's disease and dementia."

Dr. Lee and her colleagues evaluated data from nearly 3,000 participants in the ongoing Adult Changes in Thought Study for their study.

Participants in the Adult Changes in Thought Study were 65 or older and did not have dementia when they participated. The researchers checked in with them every two years until dementia symptoms or Alzheimer's disease appeared.

Kaiser Permanente Washington collected data for this study from 1994 to 2018, which was then examined between 2019 and 2021.

The study only included those who had been diagnosed with cataracts or glaucoma before to enrolment or during follow-up.

Researchers discovered that of the 3,038 study participants, 853 got dementia, including 709 with Alzheimer's disease, after obtaining information on cataract procedures from the study participants' medical records. In addition, 1,382 individuals (45 percent of the total) received cataract surgery.

Dr. Lee and her colleagues discovered that people who received cataract surgery had a nearly 30% lower chance of acquiring dementia following the procedure.

The researchers also found that glaucoma surgery had no effect on the risk of dementia.

Future dementia research and eye health

Dr. Claire Sexton, the Alzheimer's Association's head of scientific programs and outreach, who was not involved in the study, described the significance of this result to MNT:

"Previous study has shown that sensory impairments, such as visual loss, are related with an increased risk of dementia." However, this study suggests that enhancing eyesight — in this case, removing cataracts — may lessen the chance of dementia."

"There's a clear message here for clinicians that they need to examine and treat sensory impairment in their older adult patients, as well as those with Alzheimer's disease and other dementias," Dr. Sexton stated.

"Sensory function assessment should also play a part in measuring cognitive changes and diagnosing Alzheimer's." People who have sensory impairments, such as vision or hearing loss, should keep note of them and consult with their doctor. Family members can play an essential role in noticing sensory changes and supporting evaluation and follow-up."

Dr. Lee believes that these findings would raise awareness among clinicians about the importance of eye health in their elderly patients who are at risk of dementia.

"Aside from some lifestyle aspects, such as food and exercise, that are regarded to be protective against dementia, there are few recognized interventions to date," she noted.

"Older individuals who are suffering cataract symptoms, such as trouble driving at night or seeing halos around bright lights, should be checked by ophthalmologists, who specialize in eye procedures." If an ophthalmologist recommends cataract surgery and the patient is undecided, our findings show that cataract surgery would not be harmful, and there may be an extra benefit."

Is there a place for blue light?

Blue light is blocked by cataracts. More blue light can enter the eye after surgery. According to the scientists, this may have a role in lowering the risk of dementia.

Dr. Lee said that intrinsically photosensitive retinal ganglion cells (ipRGCs) are unique cells in the retina that are highly sensitive to blue light stimuli and assist control circadian cycles.

"Degeneration and altered function of these cells have been linked to cognition Source and Alzheimer's disease," she continued. "Because cataract surgery restores the transmission of blue light through the lens and to the ipRGCs, it may allow those cells to be reactivated in a way that protects against cognitive deterioration."

Furthermore, Dr. Lee believes that the retina might give a non-invasive method of diagnosing Alzheimer's disease and other dementias before clinical symptoms appear.

"Sensitive retinal indicators of preclinical Alzheimer's disease would be extremely beneficial for clinical trials of prospective treatment options," she said.

"We are now undertaking research in which we gather non-invasive, very sensitive retinal imaging in persons with and without cognitive difficulties and utilize artificial intelligence (AI) tools to interpret and evaluate the data." Our long-term objective is to create AI algorithms that can detect signals in the eye that can forecast someone's likelihood of getting dementia, such as Alzheimer's disease."