cataract

Killing Blue

Killing Blue 0

My favorite color is down for the count. Blue might have been down longer than I realize. I’ve heard of blue blocker sunglasses a long time ago but I thought that might have just been a fad of some kind. Who knew what kind of studies there were that blame blue light for causing so much damage in the eye? I admit I’m still reading a lot of studies and articles trying to sort this out. I mean, can you look at the blue sky and ever think it’s bad? That’s what seems so wrong about this.

Let’s start with the bad news (but there is good news too). The other day I was a participant in a webinar. The topic was about this newly released product called Crizal Prevencia. Now I’m skeptical of products right off the bat because I usually only get the marketing spiel. This webinar spiel was no different. It’s a coating applied to lenses in glasses that is supposed to reduce by 20% the amount of blue light in the 415nm – 455nm range. Why is that range such a big deal? Well, that group of wavelengths is pretty near the ultraviolet wavelengths (UV-A) and you can pretty much guess something close to UV isn’t exactly considered healthy (or is it?). I’m sorry but I can just see it now.  Opticians (I’m not accusing all of them) will be/are telling their customers that they need this coating because it can help prevent macular degeneration.

What is macular degeneration? It’s an eye disease in the macula, of course! The macula is this small part of our eye (in the back of our eye in the retina) that we see the best with….the 20/20 part of our vision. It’s also an age-related condition which in this case means it can occur when you’re old. UV exposure (I’ll get to blue light) apparently adds up and if you get too much of it over a life-time then you’re at greater risk of skin cancer and macular degeneration…and cataracts. I believe I read that blue light causes a cumulative effect in our retinas as well and studies show macular pigment and blue light are not very compatible. I tell ya, if it isn’t one thing that’s bad we have to go and blame the color blue now.

But there’s something more odd, but good, about blue light. Because there’s a range of other wavelengths that are still blue and some of that range is apparently beneficial. Doesn’t that just make this whole thing weird? Blue light in the range from 465nm – 495nm helps our circadian rhythm, memory and thinking. Older patients have even been told to wear glasses that allow that blue light to help with their sleep cycle. Yay for something good about blue light.

And here’s good news for those with blue eyes. Based on some studies, blondes and blue eyes are not any more prone to developing macular degeneration than brown eyes. But you can also find articles reporting the opposite. Make up your minds people! It’s hard to find the definitive answers to anything sometimes. And here’s more good news (maybe). Once we get cataracts, blue wavelengths are absorbed in the cataract just like blue blocker glasses. So the studies about macular degeneration and blue are interesting to read. There just doesn’t seem to be clear explanations about how much blue light and at what age it does it’s most damage. Studies say it’s when we’re younger. Can you really imagine seeing all those kids playing soccer wearing sunglasses?

Since this article is partially about macular degeneration I wonder if we all start eating better, don’t smoke and don’t play too long at the pool everyday, will macular degeneration decline? There are genetic factors that contribute to a lot of diseases and that includes macular degeneration so we can’t eliminate that part just yet. Just don’t stare at bright lights too long and wear sunglasses and a hat and try to get your kids to as well.

Oh, will your computer users have any problems with blue light from the LCD‘s? Oh boy. Another issue for another day.

Here’s the visible spectrum again. Find your favorite shade of blue and see what wavelength it is.

spectrum

spectrum

 

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Myopia confers protection from diabetes

Myopia confers protection from diabetes 0

The title isn’t clear. Here’s what I mean. If you have myopia, some studies show that you are less likely to get diabetes or you are less likely to have significant diabetic problems. With all the bad things that can happen because a patient has myopia, I can see how the good things might not be reported or seem important. Let me be clear though, having myopia doesn’t mean you won’t get diabetes. It just means you are less likely.

Myopia is also called nearsightedness. It’s not something I have but it’s the most common reason for patients to come to my office. They want glasses or contact lenses usually. That’s mainly why I have a job….people need optical correction to correct their vision. My job is also to check for eye diseases. Those with myopia are at a LITTLE greater risk of some problems and more so if the myopia is high (greater than -5.00). The other guys…the hyperopics (those that are farsighted) have their own LITTLE risks for certain conditions. The other common vision problem easily corrected is presbyopia and I don’t know of any diseases associated with that condition other than losing your reading glasses.

Let me clear up what I mean by risk. If you read a research article and it says the odds ratio for some condition is greater than 1.0, then the risk is higher. If the risk ratio is less than 1.0, then that person is less likely to have/develop the condition than the other group in the study. If the odds ratio is 2.0, then that means twice as many people with myopia will develop that problem than the other group in the study.

In one study I read, a highly myopic person was less likely to develop what’s called proliferative diabetic retinopathy (PDR). Let’s just say, you don’t want to have diabetes AND PDR, period. The odds ratio of having PDR for a younger high myopia person with diabetes was 0.40. That’s lower than 1.0 which means they are less likely of getting PDR. What’s interesting about this is that those with high myopia are at a greater risk for other kinds of retinal problems but in this case, they are at less risk of PDR. It might have something to do with the vascular differences the study said and the extent of a condition called posterior vitreous detachment.

There’s another odds risk for those that have myopia and the likelihood that they will even get diabetes. It was reported as 0.90. That’s less than 1.0. So myopics were less likely to get diabetes compared to the other nonmyopic group in the study.

I should tell you what those bad things are that are more likely to happen in a myopic patient though. The odds ratio varies around 2.0-3.0 for these conditions compared to those with no myopia:

retinal detachment

glaucoma

PSC cataract (that’s not the typical age-related kind of cataract)

macular disease

So, just come in and let me look or get your eyes checked wherever you are. You’re probably fine but you myopes do have a LITTLE greater chance of me finding something there that isn’t good.

I am getting (or have) the complete articles below if anyone wants them.

http://www.ncbi.nlm.nih.gov/pubmed/20031224

http://www.ncbi.nlm.nih.gov/pubmed/8302567

http://www.ncbi.nlm.nih.gov/pubmed/22772022

myopia example

myopia example

 

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