The first hard (rigid gas permeable) contact lens was introduced mainstream in the 1970s.  If you or your parent recounts their lens wearing experience from this decade, it usually is not with fond memories.  The lenses weren't comfortable, you had to clean them with much greater care, and they were a lot more expensive.  So when disposable hydrogel (low oxygen permeable) soft lenses hit the market in 1987, and then later high oxygen permeable (silicone hydrogel) soft lenses became available in 2002, many thought RGP contact lenses would go the way of the dinosaur.  Who would want hard contact lenses they kept for a year or two at a time when they could have a new, fresh, inexpensive, comfortable lens exchanged out monthly (or even more often!)?

Debris (in this case microscopic balls of mucin) trapped underneath your contact lens can result in increased risk for inflammation and infection of your eye with contact lens wear.  It's much more common to get debris like mucin balls under soft contact lenses as compared to under RGP lenses. via

The truth however, defies that expectation.  RGPs continue to make up around 7-10% of the contact lens wearing market, and the number of wearers has not been steadily declining, but instead remaining stable over the last decade.  The two biggest reasons for the resilience of RGP lenses in the marketplace are visual quality and excellent ocular health benefits.  Soft contact lens wearers suffer from microbial infections at an average rate of 4/10.000 wears per year; RGP wearers only have infections at a rate of 1.2/10,000 wears per year.  So if we are throwing away soft lenses more regularly, why do we have more infections with these lenses than the older generation RGP materials?  The answer lies to a large extent with how your tear film moves underneath the contact lens.  Tear film movement is responsible for washing away debris, bacteria, and cycling nutrients in a regular flow out from underneath the contact lens with every blink of your eye.

Understanding Tear Film Exchange

Imagine the front surface of your eye.  Your cornea is continuously coated in tear film.  That tear film expresses with every blink, moving across your eye and then drained down your nasolacrimal duct through the puncta openings in your eyelid.  The tear film helps keep your eye hydrated; it's essential for comfort, oxygen transmission, and clear vision, and also is responsible for flushing away debris and contaminants that your eye gets exposed to regularly in the atmosphere.

There are multiple layers to your tear film, and when you place a contact lens on the eye, the tear film must split to both coat the lens surface and the space between your cornea and your contact lens. via

Now imagine putting your contact lens on your eye.  When the lens sits on the cornea, it splits your tear film in half; some of the tear film now goes over top of your contact lens, but some of it remains underneath the lens, sandwiched between your lens and the cornea.  In order to properly flush "dirty" tear film off the eye with your blink, you must move not just the tear film from over top of the contact lens, but also the tear film from the behind the lens. This is the limiting step with soft contact lenses.  Tear exchange is measured in units of tear turnover time; T95 represents the time in minutes for 95% of the tear volume to be eliminated from under the lens.  The lower the T95, the faster (healthier) the movement of tear film from under the lens. Studies show the average T95 for soft contact lenses is around 30 minutes; the  average T95 for RGP contact lenses is around 5 minutes.

Why do RGPs exchange tear fluid so efficiently?  

1. Smaller Diameter:  The average RGP is about 5 mm smaller than the average soft contact lens, and because it is smaller, it is easier for tear film to move freely underneath.

   RGP lenses are typically between 9-10 mm in size via

   A well-fit soft contact lens is around 14 mm in size and covers the entire cornea via

2. More Movement on the Eye:  RGPs are properly fit to have more up and down movement on the eye than soft lenses are traditionally fit.  The properly fit RGP lens will move 1-2 mm vertically with blink.  A soft contact lens typically moves around 0.5 mm.  The lesser movement of soft lenses is one of the reasons that they are considered to be significantly more comfortable on the eye than RGPs.  Mobile RGP lenses bump against your eyelids as you blink, creating lens awareness (let's face it-- that's a euphemism for discomfort) that's a hallmark of RGP wear. But the con of soft contact lenses eliminating this comfort problem caused by greater movement is a tighter fit that traps tear film and the debris caught inside it longer underneath the lens.  This is one of the reasons that doctors must carefully assess the fit of soft contact lenses every year for proper on-eye movement.  A decrease in lens movement with blink of just 0.2 mm can increase the wearer's risk for an inflammatory or infectious event 4.5 times higher.  Just a little too tight can mean the difference between you getting an infection this year!

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It's that time of year again -- allergy season.  My patients often tell me that they take a little break from contact lenses for a week or two during the spring or summer because their eyes bother them only when their contact lenses are in.  The reason?  Contact lenses trap irritants like dust or pollen against your eye, so when your personal irritant is "in season" you are getting a concentrated dose of it as it sticks and hangs out on your contact lens all day long.  Another reason is that when we have allergies, the inner lining of our eyelids (the palpebral conjunctiva) swells in response into layers of little bumps called papillae.  These bumps rub over the contact lens with every blink, creating much more friction and discomfort than you normally experience when your eyelids aren't having a reaction.

How can you fight back against irritation this time of year?  Here are a few simple ways to improve comfort and get your lenses back to their best performance:

Ask yourself: When was the last time you threw those lenses away?
If you can't remember, it's probably been too long.  An old contact lens is going to collect significantly more buildup because the surface becomes "stickier" as the coatings to repel debris are worn away during the lens' lifespan.  This wearing off of lens coating and hydration layers is the same reason that an old contact lens causes irritation even when it's not allergy season.  Without a good surface, the aged contact lens creates excess friction against your eyelids, increasing discomfort and also the chance for ripping or rolling under the eyelids to occur.  Not to mention that you'll be seeing worse because the lens material distorts with age, and you'll be putting yourself at risk for much more serious infections. If you are entering allergy season with a 2 week lens, and it's been 2 weeks, time to throw it away and start again with a fresh lens.  If you want lenses to perform to their best, you've got to give them a chance by disposing of them properly.

Don't go to bed without removing your lenses.
Do you usually sleep in your lenses?  It's going to make it a lot more comfortable over the next few weeks if you take your lenses out at night and clean them properly.  We need to remove all of those allergens your lens collected during the day, and give your eyes a chance to recover without a pollen-coated dirty contact lens nestled against it all night long.  Think of your contact lens like an air filter. All of the air getting to your cornea has to pass through that contact lens.  If your air filter is clogged with pollen or other microscopic debris, it's not going to let much oxygen through, and it's not going to feel so good having all that trash against your eye all the time.  You can put your lenses back in when you wake up.

Cleaning: You're Probably Not Doing it Right
Imagine your normal routine.  Do you just take your contact lenses out and throw them in your case? Well, you're doing it wrong.  Multipurpose contact lens solutions like Opti-Free, Renu, Biotrue, Revitalens, Aquify, Complete, and the generic store brands require rubbing your contact lenses with solution before  you store them in the case overnight.  Without the rub, you are leaving > 80% of the day's debris still on your contact lenses!  If you look, you'll notice the box of your solution doesn't even say no-rub anymore; that's because the published research has proven time and again that not rubbing just doesn't work.

What do you do if you are great about rubbing your lenses already, but your lenses still feel dirty and uncomfortable?  Time to invest in a stronger cleaning solution like Clear Care or Peroxiclear.  You need to read the instructions carefully because these solutions can burn your eyes if not used correctly, but for most people the extra few seconds of preparation is totally worth the way the lenses feel the next day.  Another great option is a extra strength soft contact lens cleaner that you use as an additional supplement to your normal multiple purpose solution.  These extra cleaners like Miraflow or the generic version which can be found at Walgreens are great for weekly use for an extra boost. Again, just make sure you read the instructions first because all of these deep cleaning products can't be put directly into the eye without causing serious injury.

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Do Some Prep-Work
Here's a pro-tip for year round comfort: before you put in your contact lens, put in a drop of a moisturizing artificial tear.  One drop of Systane Ultra or Refresh Optive every morning before insertion gives a nice buffer of hydration between your cornea and your contact lens, and can add as much as a few extra hours of comfortable lens wear to the end of your day.  If your eyes feel a little irritated or scratchy before you go to remove the lens, go ahead and put in another drop before you take your lens out.  A lens that has dried and stuck to your cornea will feel a little irritating and like it's not moving properly, but it won't usually hurt until after you take it off and peel a layer of cornea that was adhered to the lens with it.  A drop before removal can help lift the lens up and off your cornea and prevent those painful corneal abrasions that come from a dried out lens.

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Use a Good Allergy Drop
Are your eyes itching?  Chances are, you'll need an anti-histamine or even steroid based allergy drop to control your symptoms and keep contact lens wear comfortable.  Alaway and Zaditor are my two favorite over the counter anti-histamine drops (both need to be used 2 x a day to work effectively). There are a number of great once a day drops on the prescription market too (check this post for some of the most popular).  Remember, allergy eye drops will work best if used when you are NOT wearing contact lenses, so a great time to insert your drop is before you put your lens on in the morning, and after you take them out at night.  For eye symptoms specifically, try to avoid oral OTC allergy medications like Zyrtec, Claritin, and Benadryl.  All of these oral anti-histamines will dry your eyes out as a side effect, making your contact lenses a lot less comfortable!

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Let's just say spring is looking really good for eyewear.  Here's a little sneak peak at what we can expect to see for the new year:

Dolce and Gabbana  via

Dolce and Gabbana via

Bottega Veneta via

Bottega Veneta via

Giambattista Valli via

Giambattista Valli via

Marni via

Marni via

When prostaglandin analogue eye drops for glaucoma became available mainstream in the 1990s, they revolutionized glaucoma management and became the first line treatment for most patients. Now Valeant/Bausch and Lomb has submitted a new classification of glaucoma drop treatment to the FDA for fast-track approval: Vesneo, a combination drop of the proven prostaglandin analogue class with the first ever utilization of topical nitric oxide for additional pressure lowering effect.

How aqueous humor travels through the anterior chamber via

1. The most obvious ocular health concern that you'll spot is at the macula.  See those yellow color distortions right in the center?  Those are drusen consistent with dry age related macular degeneration.  This patient came in for her annual exam with a known history of AMD that was being followed, so this macular appearance was expected.  But can you see the new issue?

2. Follow the artery (the lighter colored blood vessel) up from the optic nerve and you'll come to a whitish round circle smack in the middle of the artery wall.  This is a cholesterol plaque lodged in the arteriole, called a Hollenhorst plaque.  Luckily you can see blood passing through the artery to the other side.  If the blood vessel is white on the other side of the artery we know we have full obstruction and this would be an artery occlusion instead of just a plaque (occluded arteries are much more serious!).  A cholesterol plaque, even when there is blood passing around it, is still a potentially serious threat to vision and systemic health; if there's a blockage in your eye there is likely a risk for cholesterol blockages elsewhere too.

What You Need to Know
Cholesterol blockages or Hollenhorst plaques are often found without causing any vision symptoms, so this is just one more reason why routine ocular health checks with dilation or imaging is a vital part of everyone's preventative health care.  The patient above had absolutely no vision complaints, and unless blood flow is being blocked, likely there will be no affect on vision. If there is a plaque limiting blood flow to the retinal tissue, the patient will likely experience blacking out of vision (called amaurosis fugax or transient ischemic attacks) that can last for minutes at a time. Any sudden vision loss is always worth a call to your eye doctor, even when it is painless!

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There is no active treatment for Hollenhorst plaques in the exam chair, but finding the cause of the blockage is the first line of action. Studies suggest between 45-55% of patients with Hollenhorst plaques have significant carotid stenosis (blockage) of the internal carotid artery on the same side as the affected artery.  Your doctor will order a carotid doppler or ultrasound to detect the presence of stenosis.  If you have been diagnosed with conditions like high cholesterol, high blood pressure, diabetes, or are a smoker you are at a much higher risk of getting these cholesterol blockages due to chronic damage to your artery walls. The carotid artery is particularly at risk for cholesterol plaque blockage because it splits into multiple branches right as it enter the base of the skull.  The split into smaller passageways creates an area for cholesterol plaques to get lodged, constricting blood flow through the area.  The carotid artery is very dangerous to occlude though -- it's delivering blood not just to your eye but to your brain so a blockage here could put you at risk for serious health issues and even a stroke.

If your doctor finds carotid stenosis on your ultrasound, it will likely be treated with oral medications like anti-platelet/blood thinners (baby aspirin is a common one) and cholesterol lowering medication like the statin category of meds.  Surgical treatment is sometimes required to remove the obstruction -- typically when the carotid is > 60% stenosed surgery is the preferred treatmetn method. 

Optos retinal imaging showing a Hollenhorst plaque via

By The Numbers
While you might not notice any problems or changes in your vision, if a Hollenhorst plaque is found during your eye exam it's not to be taken lightly.  The Beaver Dam Eye Study found that those with Hollenhorst plaques or any retinal emboli were at a 3 x higher risk of fatal stroke over the next 8 years.  This is a finding not to be ignored, and just another reason that when you go to your eye doctor, you need to have retinal imaging and or dilation done every single year, even if you don't notice any problems with your vision.  An eye exam is a snapshot of your entire systemic health, and using the retina like a window into your body's inner workings can save your life.

Nonprescription reading glasses can get a bad rap -- you've seen the turnstiles at the drug store featuring bland "unisex" frames in uninspiring silver metal or black.  But wearing over the counter reading glasses doesn't have to be a fashion sentence of doom.  Today we're interviewing Angie Stocklin, Co-Founder and COO of Readers.com. Several years ago I started following Angie on Pinterest and found her to be a constant source of eyewear fashion! I was repining nearly everything she posted.  Here's her take on the best ways to let over the counter reading glasses become a stylish part of your wardrobe.

Bookworm

Brit

Allergy season is almost upon us, and itchy eyes, nose, skin, and throat is par for the course for many. But there are plenty of people out there that experience itchy, irritated eyelid skin all year round and no amount of Zyrtec or Benadryl is going to help.  In fact, they will probably make it worse. That's because allergies can cause itching, but so can dryness and inflammation, both of which are chronic and can cause you to experience red, itchy eyeild symptoms year round.

Why do the eyelids get itchy or irritated?  The skin of your eyelid is incredibly thin and delicate, and the blood vessels are quite close to the surface.  As a result, any internal inflammation causing the veins to dilate and fluid to pool under the eyelid skin is going to make a bigger impact. The thin eyelid skin swells quickly, giving you that red puffy appearance. Check out this post for more

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Another culprit to eyelid irritation is the eyelashes themselves.  Think of your lashes like little feather dusters, catching debris and keeping it away from the eye itself.  The eyelash follicle is a collection area for tons of microscopic allergens like pollen, dust, dry skin, makeup and even an inviting little home for mites like Demodex that survive off of eating your dry skin particles. Read more here. All of this is going on at a microscopic level that you aren't visibly going to see when you wash your face, and as a result, when was the last time you really cleaned carefully right into your eyelash roots? Scary, right.

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Right on the inside of the eyelash follicle in the delicate waterline area are your meibomian glands, oil glands responsible for secreting the top layer of your tear film with every blink.  These glands are easily clogged by dry skin and debris, or by anything that can harden oils like cold air, wind, inflamed eyelid skin (inflammation makes the lid margin swell and can block the gland opening), and not blinking frequently enough (like when we use computers, cell phones, or even read for long periods of time).  If your oil glands are malfunctioning, your body can even start making soaps along your eyelid margin which foam up and of course cause stinging and burning.  Keeping those oil glands open, free of debris, and properly secreting is essential to comfortable eyelids and the eye itself -- if you don't have a good tear film, your body can't blink away debris properly and you'll have worsened ocular allergies!  It's all a terrible feedback circle.

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Now that we've got the picture for why our eyelids need help, how do we clean them properly to get rid of debris and reduce irritation?  Soap and water is often much too harsh for your delicate eyelid skin, and if we are cleaning right into the lash roots, of course it could get into your eye and burn like crazy.  That's why baby shampoo was so popular for a while, but if you've ever used baby shampoo regularly for eyelid cleansing, you know it is incredibly harsh and drying for routine use.  Instead, we need a product that will clean, but won't strip all the oils from your skin and leave it parched,dry, and irritated all over again.

My Favorite Products:

Blephadex:
If you don't read anything else, just buy this.  Hands down this is the best eyelid cleansing product I have ever used.  It is coconut oil and tea tree oil based -- great for sensitive skin types and incredibly soothing.  The coconut oil will hydrate your skin while it's cleaning, and the tea tree oil is excellent for reducing Demodex colonies and inflammation.  It is an excellent eye makeup remover; you can rub it right into your lash follicles and not worry about burning or stinging.  For most people, using this product every other night will be enough on a routine basis, but if you have a lot of irritation going on you might want to use it nightly for a week to get things under control.

Pads or Foam Version via Amazon

Ocusoft: 
Before I found Blephadex I had been using Ocusoft pads for years and they work wonderfully. Excellent for nightly makeup removal, non-drying, and easy to find over the counter at your local pharmacy, Target, or even grocery store.  Ocusoft also makes an excellent pump bottle foam, a spray version for those who do better with a less aggressive approach, and even cooling gel for night time use.

Ocusoft pads have been solving eye irritation successfully for years and are easy to find over the counter at your local pharmacy or on Amazon

The HypoChlor spray or gel is a new product, great for eyes that don't need the intensity of the foaming pad and need a more gentle approach without sacrificing effective bacteria and inflammation control.  Applying HypoChlor gel at night is a great soothing way to kill bacteria and reduce eyelid swelling while you sleep. via

Avenova:

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This hypochloric acid spray is all natural and easy to use -- just spritz a few times on a cotton pad, then rub along your eyelids.  It's incredibly gentle but cuts debris and dry skin quickly without you needing to rub much at all.  This product is gentle enough for use every single day, but it kills the most common strains of skin bacteria (and even MRSA!) in under 1 minute.  If you are prone to chronic styes, this is the product for you.  I've had several patients using daily Ocusoft still get styes (a bacterial infection of the meibomian gland), and according to their data, Ocusoft can take more than 30 minutes to kill these same bacterial strains.  So if you've tried Ocusoft and are still getting styes, this prescription lid cleanser would be a great alternative.  Right now Avenova is the only product listed here that is only available with prescription, typically running about $30 at your local pharmacy.