Older adults who suffer from cataracts and get them removed will not only be able to see more clearly but may reduce their risk of developing dementia—as well as prevent the loss of cognitive functions like thinking, remembering and reasoning.
A U.S. study recently published in JAMA Internal Medicine suggests individuals who had their cataracts removed were nearly 30% less likely to develop dementia. In addition, the decreased risk persisted for at least a decade after surgery.
Lead researchers – including Cecilia S. Lee, MD, the director of clinical research in the department of ophthalmology at the University of Washington in Seattle – analyzed health data from 3,038 adults 65 and older with cataracts.
“Cataract is a natural aging process of the eye and affects the majority of older adults who are at risk of dementia,” Lee said in a phone interview with Seasons. “By learning about the eye, eye disease and health, we can better understand brain health and who may be at risk of developing dementia.”
Findings of the study
According to the researchers, participants were dementia-free at the start of the study and were enrolled in the Adult Changes in Thought (ACT) study, which has been tracking seniors in the Seattle area since 1994. The average participant was 74 years old, 91% identified their race as white, and 59% were women.
Lee noted that study subjects had received a diagnosis of cataract before the start of dementia and had at least one study visit after diagnosis.
In the results section of the study, approximately half of the participants underwent cataract extraction. The study states 853 individuals were diagnosed with some form of dementia. From these results, Lee and the authors of the study concluded the risk of dementia was almost a third higher in patients who did not have cataract surgery.
“The risk of developing all-cause dementia in participants who underwent cataract extraction was significantly lower than for people who did not undergo cataract surgery,” the authors wrote. “Given the substantial degree by which cataract extraction is associated with lower risk of dementia and its persistent effect beyond 10 years, the improvement in quality of life for the affected individuals and their daily life is considerable.”
The scientists also studied dementia outcomes in participants with glaucoma, a condition that can cause vision loss and blindness by damaging a nerve in the back of the eye called the optic nerve. They found the risk of dementia did not change or lower among participants who did or did not undergo glaucoma surgery—which does not restore vision.
To date, there are few known measures other than certain lifestyle factors such as diet and exercise thought to be preventive against dementia, according to Lee. The study suggests that eye health is important in older adults and that there may be an added benefit to removing the cataract in addition to improving visual acuity and visual function.
Next steps
Lee states her team is actively scanning patients who participated in the study with advanced retinal imaging devices that are non-invasive and fast.
The research team will also be using artificial intelligence to interpret data and retinal imaging that could be useful in screening purposes or risk precision for someone developing dementia in the future.
“I’m hoping that with these advanced tools – imaging techniques in ophthalmology, narrowing with artificial intelligence, and computer science techniques – we can move this field forward, understand what could be driving these connections between the eye and brain, what are the mechanisms, and potentially really leading to novel ideas of therapies and treatment,” she said.
Cataracts and treatment
According to the American Academy of Ophthalmology (AAO), a cataract is a clouding of the lens in the eye that is most commonly caused by aging. This occurs when proteins in the lens break down and clump together, which can cause objects to look blurry, hazy or less colorful.
Based on data from the AAO, cataracts affect more than 24.4 million Americans aged 40 and older and almost half of all Americans by age 75.
The only way to remove a cataract is with surgery, using one of two surgical options: traditional cataract surgery and laser-assisted cataract surgery. Generally, during the procedure, the cloudy natural lens is removed and replaced with a clear artificial lens called the intraocular lens.
“If an older adult is having symptoms of cataracts – decrease in vision, night driving difficulties, or blurred vision around bright lights – they should see an ophthalmologist, a medical doctor that is trained in eye surgery,” Lee said. “Having an earlier surgery would not hurt and may in fact have additional benefits beyond improved vision.”
