Comment by aaavl2821 | Hacker News Reader

Comment by aaavl2821 | Hacker News Reader

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A lot of people in the scientific community had suggested for a while that glucose levels in eye fluid were not sufficiently correlated to blood glucose levels for glucose measured in tear fluid to be clinically useful. So even if you could detect glucose in eye fluid, it wouldn't help you manage disease. In the eyes of some this was an obvious limitation that the company brushed aside, and there was a fair amount of hype around it, so there were some ppl calling it vaporware

Although some of the core tech around engineering all the sensors, battery, Bluetooth etc into a contact lens is pretty cool. There are a lot of patents from the inventor, brian Otis (who wrote the blog post), if you want to take a look.

But based on the blog post it seems like they were having trouble measuring glucose in tear fluid, which is one step upstream from the aforementioned issue around lack of correlation btw eye and blood glucose. If you can't accurately measure the analyte it doesn't really matter if it's correlated w disease

"in the eyes of some..." - thought you could sneak that by HN? I see what you did.

You saw what they did there eh?

The technology is definately more than cool, hopefully some of that tech can be repurposed into something that can make it clinically.

Worth noting, tear glucose wouldn't need to be correlated in a linear fashion with BGL, as long as there was a way to derive BGL from tear glucose data.

That is probably the catch. Tear glucose may not be all that well correlated with blood glucose.

Aside, spelling: it's definite, like finite/infinite. Think "the finite is more definite".

I think the opposite is true. To achieve medical usage the correlation should be linear. If this is not the case, a small variation of glucose could lead to big jump in the reading, which would decrease the accuracy. In real life, most of the biological system or test exist in a buffered environment, which often show a range of linear relationship for substrates, and tests are often performed by adjusting into such linear range.

If a small variation in glucose led to a big jump in the reading, then the glucose calculation would end up with greater precision.

The term "correlated" is often used as shorthand for having significant mutual information. The possibility of a nonlinear relationship is lost on very few.

I had the idea of measuring the index of refraction in the aqueous humor using something like a multi-perspective speckle interferometry on the iris.

I think with all of these non-blood approaches is that only the blood matters, and the rate of change in the blood will always be much higher than anything else.

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