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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Onions, Yawning, Wind and Emotion

Onions, Yawning, Wind and Emotion 0

Some of you already figured out what I mean by onions, wind, yawing and emotion. All of them can create tears in our eyes along with other things that can get in our eyes like little foreign “bodies” (allergens). Interestingly, contact lenses don’t seem to be one of those things that makes our eyes tear (for most people) even though that’s foreign. The complaint with some people and contact lenses is they can make the eye feel drier.

I did an earlier post about the top layer of tears, the oily layer. When our eyes tear however, what we get is the aqueous layer which is what most of our normal tears are made of…watery consistency. That aqueous stuff comes out of these little glands that are just behind the top of our eyeballs and a little to the temporal side. See the picture below for where those lacrimal glands are located. And by the way, the medical term for tearing is lacrimation which for some strange reason made me think of the medical term, micturition, which is what happens when I drink a lot of coffee. And by the way, coffee, being a diuretic, can have some effect on whether our eyes do have sufficient tears to keep them from feeling dry.

Not long ago I had a patient tell me they yawn when they feel their eyes were dry. I had never thought about that as being a way to help with dry eye before. So I looked that up and found on one site that someone doing that exact same thing started complaining of aching in their jaw muscles. Apparently this person yawned very frequently during the day. The connection between yawing and tearing is probably the extra pressure from facial muscles forcing tears out of the lacrimal glands. There’s an interesting condition that’s related to tearing only by the result which is called jaw-wink reflex (Marcus Gunn jaw winking) and crocodile tears (Bogorad’s syndrome). I won’t go into those except to say that it’s an extra nerve connection that’s unusual.

So onions…as you probably know…release something that causes our eyes to tear. It’s a combination of reactions that leads to the final production of what’s called, syn-propanethial-S-oxide (lacrimal factor). Our cornea, the outmost part of our eye has a lot of nerves and this chemical activates those nerves leading to the lacrimal gland making us tear. If you don’t cut that onion (or break up the cells that make the onion and release the lacrimal factor) you won’t tear. There are a lot of ways to reduce tearing from cutting an onion (use a sharper knife, cut a cold onion and others) but I suppose that’s one way to see if your lacrimal gland is working well. There is a tearless onion but because it’s genetically modified, it’s not FDA approved.

Wind…that just causes quicker evaporation than normal so those little nerves in the cornea become more active in sending that signal to start creating tears, in volume. Just thinking here, I wonder if you’re eyes feel dry if it would help by sticking your head out of the car sometimes. I’m not suggestion this to patients (especially if you’re the driver) but it’s a thought that crossed my mind. But I have suggested using a local humidifier which will create more moisture in the air.

Emotions can certainly make the eyes cry, and again, in large volume sometimes. Crying from emotions is an interesting result that doesn’t come from something physically acting in the eye. Crying from laughing (maybe I should have said, tearing from laughing) probably has to do with physically forcing the lacrimal gland to release tears. Goes to show you though that emotions can easily affect how our bodies respond, and quickly too. Nerve impulses can travel up to 100 m/s which is about a third of the speed of sound.

What if you have dry eyes? The aqueous tears that are produced by the lacrimal gland probably aren’t enough to help many people so crying over that isn’t going to help all that much. Besides the typical artificial tears you can buy at the store there are a few others that I want to mention. Maybe I’ll do another post about them another time but here are a couple of prescription supplements: FreshKote® and autologous serum drops. You’ll have to visit a doctor that can prescribe those for you. Serum drops are very interesting because they are made from your own blood.

lacrimal gland

lacrimal gland

 

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