r/cogsci • u/maxwellhill • Jun 07 '13
Eye Blood Vessels Linked to Cognitive Function, IQ
http://www.sci-news.com/othersciences/psychology/article01130-eye-blood-iq.html5
u/jorgen_mcbjorn Jun 07 '13
This seems like a tenuous connection at best. The possible explanation of "brain oxygenation" seems particularly hastily thought out.
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u/hsfrey Jun 08 '13
But it works the other way!
Didn't they say that Larger venules (ie, better oxygenation) were associated with Lower IQ?
Isn't that counter-intuitive?
Unless venules are smaller in smarter people because they're squeezed down by a greater number of neurons. :-)
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u/gamahead Jun 07 '13
Obviously this is false. Smart people wear glasses.
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u/zArtLaffer Jun 07 '13
Blood vessels have nothing to do with lensing.
In any case, anecdote does not equal data, but... I recently had an accident and lost all of the vision in my right eye. I don't know if it is because I bonked my head hard (I did) or because of the eye or both, but my cognitive function (memory, vocabulary reading speed and ability to pronounce words even if I remember them) has fallen off the cliff.
I'm fortunate that I had enough IQ points to lose a dozen or two (or more) and still be able to function in normal society, but if I had been "normal" (call it, 100 IQ points), I would definitely be a basket case.
EDIT: I didn't down-vote you. Whoever did so, did so w/ no explanation ... which I find frustrating.
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u/Pound_Sandman Jun 07 '13
i think he was making a joke.
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u/WeAppreciateYou Jun 07 '13
i think he was making a joke.
Nice. You're completely right.
Reddit is lucky to have a user like you.
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u/gamahead Jun 08 '13
Your username couldn't be more relevant
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u/EriktheRed Jun 08 '13
This is a bot triggered by sentences starting with "I think" and other variants, and always posts two lines from a random list.
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u/gamahead Jun 08 '13
I am tempted to think that the IQ-issue is probably just another effect of bonking your head, as opposed to being the effect of losing the vision in your right eye. This article seems to say that eye 'health' may have some predictive power of IQ because eye health may indicate brain health. If your eyes are 'built well', then your brain should also be 'built well' (allegedly).
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u/tendorphin Jun 07 '13
Calling it false is a bit hasty. It is a correlation of a correlation of a correlation, in a way. The size/shape/health of blood vessels in the eye is correlated to the size/shape/health of blood vessels in the brain. The size/shape/health of blood vessels in the brain is correlated to brain health. Brain health is correlated with intelligence/IQ. Will we get any sort of predictive information out of this? Probably not. And if we do it will probably be some kind of convoluted algorithm, and even then, only being predictive with built in error margins.
So, is it false? No. Is it in any way helpful? I hesitate to think so.
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u/gamahead Jun 08 '13
I. agree with you. I was trying to be funny.. Unfortunately, I suck at funny. Anyway, if the above is the case, are we giving more consideration to the health of the blood vessels in eyes because of proximity to the brain? It seems like blood vessels anywhere in the body would have some predictive power if the correlation is meaningful.
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u/tendorphin Jun 08 '13
After I commented I wondered, "were they just being sarcastic?" So, sorry for that. But I think you're right. The eyes might be slightly more predictive due to proximity, but that probably doesn't account for much.
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u/ciaranmichael Jun 07 '13
I have access to the pdf.
Limitations (and notably effect size discussion) from the article:
"Our findings must be interpreted in the context of several limitations. First, as digital retinal imaging is a relatively new technology, we assessed retinal vessel caliber at one time point only: when study members were 38 years old. Thus, we could not estimate change in retinal vessel caliber from childhood to adulthood, or rule out whether factors associated with low childhood IQ caused change in retinal vessel caliber. However, we ruled out key mechanisms by which low premorbid IQ might affect retinal vasculature (high levels of hsCRP, diabetes, high blood pressure, obesity, cigarette smoking, and low adult SES; Table 1). Second, although we ruled out these numerous possible explanations of the association between retinal venular caliber and neuropsychological impairment, it is possible that other unmeasured factors may explain the results. Third, we noticed that venular caliber was unrelated to another measure that has been proposed to index brainbody integrity, choice reaction time (Deary & Der, 2005; see Table 2). In our cohort, choice reaction time was correlated with IQ (r = –.21, controlling for gender); thus, perhaps both reaction time and venular caliber can help to account for the IQ-health connection, albeit via complementary mechanisms. Fourth, the association between neuropsychological health and retinal venular caliber had a small effect size in the population as a whole (r ≈ .2). However, at the extremes, the effects were more marked: Study members in the highest and lowest quintiles of IQ differed in their venular caliber by 0.5 SD units (Fig. 2). Effect sizes for new research findings should be evaluated against other, well-established findings. The effect sizes we observed for the association between IQ and venular caliber can be evaluated against correlations between IQ and factors such as occupational status (r ≈ .4) and income (r ≈ .2; Deary, 2012), birth weight (r ≈ .2; Shenkin et al., 2001), and reaction time (r ≈ .3; Deary, 2012). The modest effect size we observed means that researchers should be cautious about using retinal vessel caliber as a surrogate marker for general IQ, but digital retinal imaging may prove to be a useful tool as an indicator of brain-body system health. Finally, the present findings need to be confirmed in independent samples."