Could you reduce your dementia risk by having cataract surgery?

How do cataracts form?

A study published last month has revealed that there is a significant link between having cataract surgery and lowering your risk of dementia. It’s been suggested that those who have cataract surgery have a 29% lower risk of developing dementia than patients who do not opt for cataract surgery. Before we delve into this science, it’s important to discuss what cataracts are, how they form, and how they can be treated.

A cataract forms when the natural lens in your eye becomes cloudy due to broken down eye tissues and proteins clumping together. This is characterised by symptoms such as:

• Light sensitivity
• Fading colour vision
• Cloudy or blurry vision
• Deteriorating night vision
• Halos appearing around bright lights                                                    

These symptoms will worsen over time and, if left untreated, will lead to blindness. Cataracts are actually the world’s leading cause of blindness, usually beginning in a person’s 60s or 70s, although they can occur earlier. Thankfully, cataracts are easily treatable with cataract surgery. This is a simple surgery, taking around 15 minutes per eye. Your eye’s natural lens is extracted, along with the cataract in it, and it is replaced with a clear artificial lens to sit inside your eye. Not only does this remove the cataract, but it prevents one from forming again in your new lens.

What is dementia?

Dementia is a syndrome characterised by the on-going decline of brain function. Some of the symptoms, as noted by the NHS, include:

• Memory loss
• Slower thinking speed
• Loss of mental sharpness
• Difficulty understanding
• Erratic mood swings
• Impaired movement
• Problems with speech

In patients with dementia, there is damage to the brain cells, preventing the brain cells from communicating effectively with each other. Dementia is actually an umbrella term for loss of memory, covering different associated conditions such as Alzheimer’s, Lewy body dementia, and more. Dementia typically occurs after the age of 65, which coincides with the general age for cataract formation too.

How does cataract surgery lower your dementia risk?

Last month’s study into the impacts of cataract surgery on your risk of developing dementia was published in JAMA Internal Medicine. The study was carried out over the course of several decades, subjecting participants to memory tests at regular junctures. Researchers studied over 3,038 men and women who had been diagnosed with cataracts, were over the age of 65, and did not have dementia at the time of the study. Almost half of the participants (1,382 to be exact) went on to have cataract surgery. These participants were found to have a 29% lower chance of developing dementia in the coming years than their non-cataract-surgery counterparts. Crucially, this lower risk persisted for at least a decade after surgery. But the real question when it comes to these findings is why?

There are a number of theories which have been floated when it comes to explaining the results of these studies. It is well-known in the world of dementia research that loss of vision leads to cognitive decline. This usually occurs as a result of reduced socialisation, exercise, reading and more, all of which have been found to increase the likelihood of developing dementia. In fact, poor vision was found to reduce brain input, “leading to brain shrinkage, also a risk factor for dementia”. Cataract surgery has been seen to increase grey matter in the brain, which plays a part in reducing your risk of developing dementia.

There is also the theory of blue light exposure – or lack thereof when it comes to cataract patients. Sunlight is the main source blue light but nowadays it can also be emitted from manmade sources such as LED lights and digital screens. Cataracts block blue light from the eye, depriving cells in your retina which rely on blue light for cognition and to regulate sleep cycles. The theory here is that cataract surgery, during which­­ the cataract is removed, could “reactivate” these cells, therefore reducing dementia risk.

Questions have also been raised around the validity of attributing these dementia-reducing benefits to cataract surgery alone. However, researchers decided to investigate the effects of glaucoma surgery on dementia risk and found that it didn’t make a difference in the way that cataract surgery does. Like cataracts, glaucoma has the potential to leave the patient completely blind if left untreated, but the fact that glaucoma surgery has “no effect on dementia risk” proves that simply being well enough to undergo eye surgery cannot be a factor in having a lower risk of developing dementia.

Dr Cecelia Lee, an associate professor of ophthalmology at the University of Washington, notes that “the brain is very strongly connected to the eye” and that they share the same neural tissue. This suggests that “some of the changes we see in the eye might reflect processes in the brain”. Perhaps restoring youthful vision through cataract surgery has similar effects on the brain?

To find out more about cataract surgery at Optimax, you can read further information on our website. If you have any specific questions, check our cataract surgery FAQs, email us at enquiry@optimax.co.uk, or give us a call on 0800 093 1110. We would love to help with any queries we can.