Older People Who Get Cataracts Removed Have Lower Dementia Risk (newscientist.com) 70
Older people who have cataract surgery to improve their eyesight are less likely to develop dementia afterwards. From a report: The effect could be because people who lose their eyesight typically spend more time at home, and so get less mental stimulation -- or it could be down to a strange effect that cataracts have on the colours that reach the retina at the back of the eye. Cataracts, which involve the lens of the eye becoming more cloudy with age, are one of the most common causes of vision loss in older people. They can be fixed by surgically removing the lens to replace it with a plastic one. Sight loss was already known to be a risk factor for developing Alzheimer's disease and other forms of dementia. Cecilia Lee at the University of Washington in Seattle wondered whether cataract surgery would have a noticeable correlation with dementia incidence.
Correlation isn't causation... (Score:5, Insightful)
Does any really believe this any more? And the there's the 3K sample size, pick the group right and you can show anything...
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Re: Correlation isn't causation... (Score:3)
I did so last year. I spent extra on toric lenses to correct my astigmatism, and my distance vision is now better than at any time in my life. Colors are more vivid, as is depth, and just about every time I take in a vista, I stop, stare and think "wow". A year on, it's still brand new.
Close vision now requires reading glasses, but they're cheap lightweight ones ($15), compared to my old few-hundred-dollar bifocals. They're close to disposable.
An interesting corollary: since everything is in new focus, my m
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Can you see in UV now?
Re: Correlation isn't causation... (Score:2)
No, but my eye beams can weld aluminum. You have to upgrade for the ferrous metal and titanium capability, though
Re: Correlation isn't causation... (Score:2)
Actually, don't know if your question was a serious one.
Serious answer: no new receptor cells have appeared, to my knowledge (or expectation), and if the new lenses extended my sensitivity into the near-UV, I don't know how I'd tell anyway, not having measured my violet response as a baseline before surgery.
I could ask people around me "can you see that?", but I'm already doing that while having my wife dress me when color is important, for my mild colorblindness. The new lenses did nothing to change that (
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Re: Correlation isn't causation... (Score:2)
Interesting. I haven't noticed any additional violet glow. I haven't been near any black lights either.
No guarantee I have that brand of lenses.
Gonna have to go find a still-open mall with a Spencer Gifts, I guess.
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I thought I remembered a WWII anecdote about this. Something to the tune that back in WWII cataract patients had extended UV vision, and in England they used UV searchlights at night and had post-cataract people looking for Germain planes. The pilots couldn't see the searchlights.
Before posting I tried to look it up and failed, however there was a similar story from WWI. See #11 here: https://military-choice.blogsp... [blogspot.com]
Re: Correlation isn't causation... (Score:2)
Interested in how this would work.
My Dad had cataracts done before intraocular lenses were available (late '60s-early '70s), and wore coke bottle glasses for the rest of his life.
If they were glass lenses in WWII and before (as seems likely), that would seem to let out the possibility of passing UV light.
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I believe glass isn't friendly to UV, but other things are. One might presume that they knew this back then and had the right optical materials available. Your "coke bottle" comment makes sense, because the "retrofit" for UV-capable lenses becomes feasible.
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I stop, stare and think "wow".
Don't stop and stare too long, people will think you have dementia. :-)
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A year on, it's still brand new.
This would be true as well if you had dementia.
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Re: Correlation isn't causation... (Score:2)
First suggestion: select your doc carefully. Get the best your insurance will cover. You want someone experienced, but not so far away from school that s/he has no knowledge of modern practice. CME helps practitioners keep up, but it's a balance. Try and find a physician who's also published, comes from a reputed good med school. Look for reviews, but understand that they're often curated, and are not the only measure of a good doc. Every doctor has some unsatisfied patients, so a bad review or two - have t
Re: Correlation isn't causation... (Score:2)
It makes total sense (Score:5, Funny)
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When you think about what is actually going on here, this kind of correlation makes perfect sense.
Sensory decline is common in old age, and people who start to lose some of their senses are less able to cognitively engage with their surroundings as those senses relay surrounding information to him or her,and it is hardly surprising that this inability can lead to the cognitive decline we associate with dementia.
While getting cataracts removed is not directly responsible for holding back dementia, it su
Cause is reversed [Re:Correlation isn't cause] (Score:5, Interesting)
Or a simple explanation is that the causation is reversed: people who have early stage dementia are less likely to get cataract surgery.
Cataract removal is elective surgery, and in the US, there are a ton of hoops to jump through and insurance obstacles for getting elective surgery done. This is going to be a serious barrier to somebody who is in the early stages of dementia.
But an even simpler explanation is just that people who get cataract surgery are simply higher income than those who don't. The correlation between health and income (or social class) is already well known:
https://www.neurologyadvisor.c... [neurologyadvisor.com]
https://www.alzheimersresearch... [alzheimersresearchuk.org]
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I would argue that is a far more complex explanation than the one I offered.
It is a far simpler supposition that sensory loss at an advanced age, where the brain does not have as much plasticity and is less able to adapt, leads to declining levels cognitive usage insomuch as the person would otherwise mentally engage with their surroundings utilizing that sense, and that declining cognitive usage directly leads to increased rates of cognitive decline than to presume that cognitive decline can somehow be
Re: Cause is reversed [Re:Correlation isn't cause] (Score:2)
"quick...where's my razor?"
- Occam
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Exactly.
The brain is entirely responsible for how we perceive the world, and we obtain that information through our senses.
Sensory loss invariably leads to disuse of cognitive functions that person has spent a lifetime utilizing. This disuse is particularly pronounced the older that a person is. This decline in cognitive functionality further causes *more* cognitive decline unless the circumstances that lead to the original cognitive loss are rectified. This feedback loop in turn creates what we ca
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Or a simple explanation is that the causation is reversed: people who have early stage dementia are less likely to get cataract surgery.
this. one has to make the choice to have the surgery. dementia patients may be less likely make this choice, or any choices about anything. they are often preoccupied with things besides vision levels.
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Yes, it's a retrospective study. But this an interesting enough finding (the effect size is pretty big) that maybe it makes they can get funding to test cataract removal in people who could not otherwise afford it to see if it makes a difference. No one is saying this is the final answer here; as the authors say in the paper (emphasis mine):
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BTW multifocal lenses are not worth the extra cost
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Technically the standard model and relativity are both time symmetric (with a few exceptions) but if you're correct that's still a pretty big discovery.
Diagnosis comes after onset [Re:Cause is reversed] (Score:2)
Technically the standard model and relativity are both time symmetric (with a few exceptions) but if you're correct that's still a pretty big discovery.
While the summary states that they develop dementia afterwards, the actual data shows that they are diagnosed with dementia afterwards.
Diagnosis occurs after, and usually many years after, the first onset of symptoms.
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When you think about what is actually going on here, this kind of correlation makes perfect sense.
Sensory decline is common in old age, and people who start to lose some of their senses are less able to cognitively engage with their surroundings as those senses relay surrounding information to him or her,and it is hardly surprising that this inability can lead to the cognitive decline we associate with dementia.
Indeed. The same sort of correlation is seen with hearing loss as well, and was discussed here a couple years ago.
https://science.slashdot.org/s... [slashdot.org]
Anecdotally speaking, my 94 year old mother has very advanced Alzheimer's, and is nearly deaf. The idea there may be related is not lost on me as they have progresses very much together over time.
Yes exactly (Score:1)
People who take care of themselves are in better condition, news at 11.
Re: Correlation isn't causation... (Score:2)
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Just that you are paranoid does not mean most or even much research is bad.
Re: Correlation isn't causation... (Score:2)
There is a flaw in the study, but it is not the sample size. The issue is that they picked 3000 people randomly and checked which of them eventually got cataract surgery. Correlation is not always causation, but often it is at least an indicator of some overarching process that binds the two measurements. In this case it does look like people who were recommended or opted for cataract surgery got less dementia. It could be that since they didnâ(TM)t have mental decline, they cared more about being able
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Understanding statistics isn't the same as understanding the mechanism(s) involved.
Medical science has a science problem (Score:4, Insightful)
How does one test causation here?
Randomly offer people eye surgery or keep them blind?
No?
Ah. So this is a retrospective study. And if there were some causal factor that correlates to both dementia *and* the decision/suitability to undergo eye surgery, then there you go: a clickbait-ready retrospective analysis waiting to be published.
Cause:effect (Score:2)
I've read a variety of studies along the lines that activity (mental, physical) slows down dementia onset. If you can't see very well, you surely ain't gonna do much...
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A controlled experiment to test for causation would be extremely expensive. No one has any financial incentive to do it.
A retrospective study is just an SQL query on preexisting data.
Re: Medical science has a science problem (Score:2)
That preexisting data often exists as a low-dimensional manifold in a higher dimensional space. That alone can fool one into thinking they've sampled the space when they haven't and discovered a causal relationship when they haven't.
Knowledge costs money to wrest from the universe. On that I'm sure there's agreement.
Re: Medical science has a science problem (Score:2)
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There's a kind of indirect causation.
People who experience sensory loss, particularly at an advanced age where the brain is simply less able to adapt to the experience, are less able to cognitively engage in their surroundings as that particular sense would have relayed it. This inability translates directly to cognitive decline that we associate with dementia.
Re: Medical science has a science problem (Score:2)
That's plausible. What's also plausible is that age is correlated with dementia and surgical intervention of any kind is inversely correlated with age: some people (or their caregivers) decline to go through the hassles of elective procedures for some people who are too old for this shit.
How does one tell the difference in a retrospective analysis?
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What's a simpler explanation, that declining cognitive usage (which may initially be caused by sensory loss at an advanced age, where the brain is less able to adapt) leads to even higher rates of cognitive decline (in a kind of feedback loop), or that otherwise declining cognitive usage somehow leads to people not choosing to have surgery?
The latter requires some kind of explanation for why that would be the case, and in turn may rest on a lot of supposition. The former does not.
Occam's Razor
Re: Medical science has a science problem (Score:2)
Occam's razor cannot create information out of thin air.
If two explanations are both plausible (and they would be deemed plausible from anecdotal evidence, otherwise there would be no questions to be answered), the prettyness or parsimoniousness of one or the other cannot be the only criterion used to decide likelihood.
The typical use of occam's razor is to dismiss an explanation that would require the existence of other phenomena that is not observable or otherwise irrelevant or creates more uncertainty th
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I'm not creating any information out of thing air here.
I'm suggesting that it seems obvious that declining use of cognitive functions ought to result in even more accelerated rates of cognitive decline.
And because in older people, the brain is not as plastic as it is in one's youth, a person who has spent a lifetime using a particular sense only to ultimately have that sense decline in ability is likewise losing a part of their ability to cognitively interact with the world insomuch as that sense would
Re: Medical science has a science problem (Score:2)
Ok , so whatâ(TM)s the prevalence of dementia in blind people then?
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It depends on when they developed blindness,
As I said, it is more likely if experienced at an advanced age, where the brain is less able to adapt to it.
I would be astonished if you could point to any evidence that showed that vision loss at an advanced age was *not* correlated with dementia to at least some statistically significant degree.
Re: Medical science has a science problem (Score:2)
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And that is why there is an original scientific publication. Which will describe all these factors. Oh, you were not aware researcher do _not_ do research in order to generate click-bait?
Medicine is not Science (Score:2)
How does one test causation here?
They don't because medicine is not really interested in that. The focus of medicine is improving people's health. They do not care about why their cures and treatments work just as long as they do. If something in the chain of events surrounding cataract removal prevents dementia that's good enough for them which is why they find a non-scientific result like this interesting. To a scientist, this sort of result is almost useless though since it leads to no increase in understanding - although it could sugg
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I'm thinking about selling my catamaran. (Score:2)
Re: I'm thinking about selling my catamaran. (Score:2)
Given the way a boat eats money, you're clearly demented if you keep it.
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People who want to read aren't in decline (Score:3, Insightful)
The Wallet Angle (Score:2)
Also, those with enough money to have the surgery can probably afford better care in general, making them overall healthier, and thus less like to have Alz.
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Keep your brain working. (Score:2)
I would hypothesize that dementia could be an effect in part of not exercising your brain, learning new things, challenge things that you think is true, pick up new skills etc...
If you have cataracts that are preventing their vision, they are cut off from reading books, exploring a good part of the world, a lot of today's technology is visual based, as well learning new hobbies often require site.
If you live your life with listening to Church, TV and Radio as your primary source of learning, you are going
Mod parent up! (Score:2)
This, exactly.
It would genuinely astonishing if the kind of correlation described in the summary was *not* present.
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I would mod this up as well.
About 4 years back I had RLE surgery. At the time my cataracts had not fully formed so insurance wouldn't pay for it. So I was out of pocket about $12,500.
Totally worth it. I had worn glasses and contacts all my life since age 8 or so but there is nothing a prosthesis like those can do for getting gradually dimmer vision. After the treatment not only did I not need corrective lenses anymore I felt I could engage with the visual world more. I felt there was more light.
Re: Keep your brain working. (Score:2)
I opted against the multifocals for torics (for my astigmatism), and am really happy with the choice.
Nothing wrong with your choice, of course. It's really for the individual to decide. I quickly decided that one eye close-one eye distant would drive me nuts (temperamentally, I'm a straightener of picture frames...)
Like you, I feel there's more light. I found a new world revealed, very happy.
Or maybe.. (Score:2)
People with active minds need to be able to see clearly. People with dementia don't care as much
Great news! (Score:2)
Combing this with Viagra will solve all my future mental ills!
https://science.slashdot.org/s... [slashdot.org]
Perfect example of false causation (Score:2)
I will bet you $1,000 that this is false causation.
Because People with the early signs of dementia will be less likely to:
Notice the cataracts early
Have money to get examined, let alone get it fixed
Decide to fix the problem
and more likely to
have an underlining issue that creates both the dementia and the cataracts, i.e. living in a poor/polluted area or take less care of their health.
Patients with dementia don't seek cataract surgery (Score:1)
People trot out the whole "correlation isn't causation" thing as if to suggest that finding correlations is useless and misguided: it is not. it is an excellent way to find possible causes. In this case though, there is a more simple reason for the observed correlation. It isn't that improved eyesight improves mental health, but rather that if you are developing dementia you are less likely to seek out treatment for declining eyesight ( i.e it isn't "seek cataract surgery" => NOT dementia, but
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Correlation is the *only* way of discovering causal relationships.
Typically dementia studies use decently long time intervals between when they look at possible early predictors and the actual onset of dementia. I didn't read the paper, but the article says this one used "up to 8 years." The paper should say what their actual criteria was. It's not impossible that you could get a whiff of correlation from very subtle, very early effects of dementia years before conventional onset, but it's not terribly like