Eyedolatry: February 2014

Myopia May Be Reversible?

Chicks have long been used to help investigate refractive error
development since their ocular model closely resembles the
development of our own via

So little is really understood about the progression of myopia (near-sightedness). Many of my patient's parents are quick to blame computer games and the large amounts of homework required by schools as to why their children's vision is getting worse from year to year, but these culprits are too simplistic. Genetics, environmental influence--it seems to all be connected. But new research points to a surprising new potential culprit -- light.

Around 2011 several reports came out linking myopia to reduced sunlight exposure in studies performed with baby chicks. Sunlight, it appears, increases the rate of release of retinal dopamine, which inhibits growth rate of the eye. Myopia is a result of light falling in front of the retinal photoreceptors, most often due to a longer than normal eyeball. The more the eye grows, the more near sighted a person will be. Researchers suggest 10-14 hours per week of outdoor light exposure may help slow myopia progression, but more studies need to be performed for this effect to be truly demonstrated.

A new study published in December takes our understanding of light's effects on myopia to a new level. In their experiment, Foulds et al separated baby chicks into red light and blue light exposure groups with a 12 hour on/off cycle for a period of 2-6 weeks. The results were amazing -- the red light group showed marked progressive myopia and the blue light group showed progressive hyperopia (far sightedness). And then they did something even more impressive -- by putting the red-light raised chicks with now high-induced levels of myopia in blue light for 3 weeks, they reversed the myopia. The same held true for reversing the hyperopia.

So what does this mean for us? We are a long way from putting your child under blue light for 12 hours a day, but we are beginning to understand what is happening on the neurologic level of the eye when refractive error is created. So many of our methods of reducing myopia have shown limited response, but maybe the future looks brighter. If you are worried about your child developing high levels of near sightedness, my best recommendation to you is get them involved in outdoor sports. Wear proper sun protection of course, but the more time spent outdoors with ambient light levels, the better your child's chances look for a lower prescription!

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The Patient's Guide to Pink Eye

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Red, watery, matted shut in the morning, and just uncomfortable. "Pink Eye" as we so affectionately label an infection or inflammation the eye is so common this type of year, I am averaging a few cases a week. But for such a common ocular ailment, it is surprising how little the average person really knows about it. For curious minds, here is what you are really dealing with:

A classic viral conjunctivitis (or pink eye) appearance via

Pink Eye is a slang designation typically used to refer to any type of conjunctivitis (an inflammation of the conjunctiva which is the clear vascular layer that lies on top of the white of the eye). Far and away the most common culprit is a virus, but bacterial and allergic conjunctivitis are also differentials that a trained eye care specialist will be able to detect. Viral conjunctivitis typically has a tell-tale symptom pathway, so here's what we are looking for:

Red eye with watery discharge (thick mucus discharge is more typically bacterial)
Starts in one eye and spreads to the other within a few days
May have swollen lymph nodes, a recent cold, or recent interaction with someone who was sick
Typically seen in children or people who are around children in their daily life

Here's the thing about viral conjunctivitis: there is NO treatment that is curative. That's right, when you go to the doctor and they prescribe you sulfacetamide or polytrim, those are antibiotics. And you have a virus. Do you know what an antibiotic does against a virus? Nothing.

Most of my patients that go to a walk-in clinic, or even their primary care provider get prescribed a low-strength generic antibiotic for their viral conjunctivitis, and they aren't really educated as to why the doctor is writing this Rx. The antibiotic won't kill the viral infection. But your doctor doesn't have any medicine they can give you anyway, and antibiotics are cheap. The best they can hope to do with an antibiotic is to prevent a secondary bacterial infection (unlikely) but really, it is typically prescribed as just a "that's all I can do" mentality. It can't really hurt, and they don't have anything that can really help. This idea of "not hurting" though is debatable with all the recent data of antibiotic resistance, but I digress.

Personally, I think this borders on false advertising,
but if you read the fine print they never promise any
more than just "symptom relief". Most people
just see "pink eye" on the box and think they are
getting some sort of medicinal treatment incorrectly.
It's really our job as the doctor to educate
the limits of these OTC drops.
via

If you see an eye care specialist for viral conjunctivitis, you won't be getting an antibiotic prescription alone. What would really work better is a steroid eye drop at relieving the symptoms, and this is what I typically prescribe if my patients want an Rx to feel better faster. Steroids won't get rid of the virus either, but at least it lessens the redness and crusting so your eyes feel more normal. You will still be infected, and still be contagious (just as you are if you use an antibiotic drop), but your eye will feel better because it is less inflamed.

Rewetting drops are a more non-aggressive treatment option, used to simply flush viral cells off the eye. You can use any over the counter moisturizing drop, but I especially like preservative free tears due to their lack of toxic preservatives that could further irritate the eye. Are you thinking of buying an OTC "pink eye" drop like Similasan? It's just a lubricating effect with a small amount of vasoconstrictor action (shrinks the appearance of blood vessels temporarily) achieved with a belladonna extract. Yes, belladonna, so that means if you get an enlarged pupil while using this stuff you used enough to actually dilate your eye. Again, it will not treat the virus. It just moisturizes your irritated eye and superficially makes your redness decrease (temporarily) by shrinking the diameter of the blood vessels on the eye's surface. I personally like preservative free artificial tears better than these "red eye relief" drops that are misleadingly packaged with a "pink eye" label as if they were some sort of treatment, because at least with preservative free lubricants there are no irritants or dilators on board that could make your eye feel worse.

If you have a viral conjunctivitis, the most important thing you can do is wash your hands. You are contagious for about 7 days from the onset of your symptoms, so try to avoid infecting others and re-infecting yourself. That means frequent hand washing, avoid eye rubbing, and wash your pillowcase every morning if your eye was weepy overnight. In 1-2 weeks your body will fight off the virus even without treatment, and you will be back to normal.

If you are a contact lens wearer, it is best to avoid lens wear while you are infected, not just for your own comfort but because bathing the contact lens in viral cells all day long, which in turn just locks those viral cells against your eye's surface with nowhere to go, is just going to keep you infected longer.

In some severe cases of virus, a betadine treatment in office has been shown to greatly reduce the viral load in the eye. But again, this is not something that you can be prescribed to use at home, and it can be very irritating and toxic to the eye to use a betadine flush. Your eye doctor will be able to discuss pros and cons with you if you are in need of this more aggressive treatment.

Remember, only a trained doctor with the correct equipment to examine the eye can differentiate your conjunctivitis from viral, bacterial, or allergic. The treatments for these different types of "pink eye" are vastly different, so I can't encourage you enough to be seen by a professional who can get your eyes back to normal and healthy as fast as possible.

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