The Importance of Retinal Imaging

Over the past 15 years, the use of retinal imaging has become more and more prevalent in the modern optometric practice.  Unfortunately, most vision insurance plans don’t cover it.  So, it’s almost always an additional expense.  For this reason, sadly, many patients opt out of receiving this additional procedure.

The additional procedure of retinal imaging (and it’s associated cost) are not a way for the eye doctor to pad your bill, however.  It’s actually an incredibly useful tool for eyecare professionals to not only diagnose additional vision issues, but also greater health concerns.

Why Are Retinal Images Important?

Doctors need to take a look at your retina during your exam.  This is important for spotting issues which could adversely affect your vision.  But possibly even more important, the retinal exam allows the doctor to spot overall health issues.  The smallest visible blood vessels in the entire body are located in your retina.  Because so many of our health issues present themselves in blood flow, this allows your eye doctor to spot health problems such as diabetes and high blood pressure before even your primary care doctor can spot them.

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Anecdotally, I even once treated a patient who had his physical the same week as his eye exam.  The physical presented that he had a clean bill of health and no concerns.  Our retinal exam spotted a blood clot…a stroke waiting to happen.

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Example of Arteriosclerosis in digital retinal image

So Why Digital Imaging?

Before the advent of modern digital imaging, doctors had to dilate your eyes, and view your retina while wearing the BIO (Binary Indirect Ophthalmoscopy).  The doctor would view your retina using a magnifying lens and a head lamp.  This would allow the doctor view the retina in very high detail, but viewing very small segments at a time.

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The advent of more and more advanced digital imaging, such as optos, now allow for the retinal exam to happen without dilation being necessary.  Not only this, but the digital retinal imaging allows us to capture the entire retina in a single image.  By capturing the entire map, there’s no question of anything being missed while sweeping across the retina with a smaller view.

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Healthy Retina captured on optos

One of the most valuable aspects of a digital retinal image is overlay.  When you have the image taken over subsequent years, each image can be digitally dropped on top of the original image, and any minute changes can be compared and documented.  Some of the most concerning aspects of retinal damage can most easily be spotted when comparing images from year to year.  When you opt for a dilated exam, instead of the digital image, we cannot overlay images because all the doctor gets to see is the retinal with their own eye and cannot document it with a photograph.

Digital Image Critical for Diabetics

For a diabetic, it is absolutely critical to get the digital retinal image every year.  I am diabetic myself, and even though I’m only in my mid-40’s my most recent optos image found the beginning stages of diabetic retinopathy.  This particular eye condition has an end result of partial blindness and can be minimized by better maintenance of blood sugar levels.

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Diabetic Retinopathy (red dots)

This is a great example of an eye condition which can be managed and observed best by comparing images from one year to the next.  This allows your eye doctor to track any small changes in the growth of the retinopathy, and recommend treatment based on the advancement.

You’ve also seen me talk about the dangers of Harmful Blue Light and it’s relationship to developing Age Related Macular Degeneration (AMD).  This is another eye condition most easily diagnosed and treated with the comparison of digital images from year to year.

Take Away

There is tremendous value for the eyecare professional, as well as for you, the patient, in getting the digital retinal images at your routine annual eye exam.  It’s not an upcharge to grift more money out of you.  This is an invaluable tool which allows your doctor to diagnose and treat not just vision related concerns such as detached retinas, but also overall health concerns such as diabetes, hypertension, and even blood clots!  It’s a very small price to pay for the peace of mind which could prevent much great vision and health concerns later on.

Thank you to optos for providing imagery in this post

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The Dangers of Mishandled Contacts

Cosmetic_Contact_Lenses

My primary focus at the OpticalJedi will always be on eyeglasses, but today I’m taking a small foray into the realm of Contact Lenses to discuss care and maintenance…and sourcing of contacts.

There has recently been many advertisements on Facebook and Twitter for a new contact lens company.  They claim to be able to provide the exact same contacts you’ve always been wearing at a dramatically lower cost.  I am not here to say whether or not their product is good.  But I’m here to provide some warnings about getting contact lenses from a source of this nature.

Contact Lenses are a Medical Device

The FDA has categorized contact lenses as a medical device.  And for good reason! Contact lenses fit directly onto your cornea.  This direct contact with an exposed portion of your body creates many risks that do not exist with eyeglasses.

When a corrective lens sits directly on your cornea, it creates a warm, moist area ideal for growing bacteria.  If lenses are not cleaned regularly (daily disposables excluded for obvious reasons) the contact lens acts as an incubator, allowing bacteria and viruses to grow and multiply at an alarming rate.  Wearing contact lenses when you are sick, can be a dangerous proposition.

Even I, an eyecare professional, had a problem with an eye infection because of contact lens use.  I thought I had fully recovered from a flu, so I started wearing my contacts again.  I had been mistaken.  I ended up with a viral flare incubated under the contact lens which created a corneal ulcer.

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Corneal Ulcer

It may not look like much, but a corneal ulcer is extremely painful, creates strong photophobia (light sensitivity), and in my case, led to my developing a reaction to most contact lens materials.  I could not wear contacts for a full 10 years after this happened.

But What If I’m Only Wearing Them For Halloween?

The American Academy of Ophthalmology(AAO) warns that many of the decorative contact lenses that can be bought online and may not be approved for use by the Food and Drug Administration. (Contact lenses are considered “medical devices” by the FDA and are regulated. Ones that are sold over-the-counter without a prescription are unregulated and technically breaking the law, per the FDA.) – Source:Self.com

The Halloween contact lenses can be even more dangerous.  Contact lenses are more than just a prescription correction.  There are additional parameters which effect how the lens sits on your eye.  Everyone’s cornea has a slightly different curvature.  If the lens does not match the curve of your eye, it can be very uncomfortable, or they might not even stay in the eye, if the curve difference is too extreme.  When you order your contacts online, even if they have no correction, the curve and diameter measurements have to work for your eye or you run the risk of at least uncomfortable lenses, and at most an infection.

The additional concern you need to watch for, if you order contact lenses online, is that they may be made with potentially dangerous chemicals not found in more reputable brands and sources:

They can also contain potentially harmful ingredients. Research published in the journal Eye & Contact Lens in 2015 found that non-prescription contact lenses can contain chlorine and iron, among other potentially toxic ingredients, which are used to tint and create patterns on the lenses. During the study, scientists found that one pair seeped chlorine after a routine rinse, and others had an uneven texture that could scratch the surface of the wearer’s eye.

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Keratitis Infiltrates

It’s very important to keep in mind that the pigments and dyes used to paint the lenses for theatrical/Halloween can be very dangerous, or even outright poisonous.  The best way to make sure the lens you are using is safe, is to get it from a reputable eyecare professional.  Also keep in mind, if you wish to get cosmetic contact lenses for a Halloween costume, it can take as long as 3-4 weeks to have them manufactured, after you have your contact lens fitting.  If you need them this Halloween, you need to order ASAP.

 

 

In Which a Theme Develops

So, it looks like we’ve stumbled onto a new segment here at the OJ…Ask the Jedi is now a thing.  

I received another email today with some additional questions on fitting advice.  Here you go.

Today’s Email

Hi Jedi Master!

I read the “A Piece of Correspondence” article and appreciate all the specific advice you provide to us consumers as to lenses, frames, etc. I myself don’t have my actual prescription in front of me, it’s totally inadequate info but I remember being told two years ago that I was a -9. In other words, a blind bat with a high minus. I will be trying a VSP doc next February, but have had some talks with his office people beforehand. I went ahead and purchased a Prodesign 4729 frame, which I have been told works from a size standpoint (47/19/145 with a 39mm vertical measurement). That being said, the width of the frame where the lenses fit into (does that even have a name?) is somewhat smaller than my current Moscot frame. The Moscot measures 4-5 mm, while the Prodesign (which I don’t have in front of me) is probably 2-3 mm. Considering that my optometrist is going to probably going to recommend a Shamir Autograph III progressive in 1.74, do you believe those lenses will fit into that Prodesign frame, both practically and aesthetically?

A few more questions, if you don’t mind: 1) my current Moscots suffer from a bad case of “ring glare” on the inside of the frame, it’s the first thing you notice. My memory tells me we did a satin polish, which did not help. There’s not much on the subject, but the Jedis on [a professional optical site] seem to recommend not polishing the lenses at all. What do you think? If so, is it still possible to roll the lenses and to polish the visible edges of the lenses only?; 2) I am definitely going to get Transitions Signature, but the 1.74 lenses reduce my AR coating choices. My optometrist says he prefers Unity (a.k.a. VSP) coating over the Shamir’s, but he did not specify which coating. The only one I can seem to read anything about is the new Techshield Blue. I am not so much concerned with Blue Light protection (which is provided in some measure by the Transitions) as having the best AR coating available for 1.74 lenses. Any feedback? I don’t believe any Crizal is available at all in 1.74, but I could be wrong. I know you would need my full prescription to really choose, but is it worth it perhaps to drop down to 1.67 for the greater choices of AR coatings? On the other hand, I like thin lenses.

My Response:

Thanks so much for reading my blog! First things first, while a -9.00 is strong, my mother was a -13.00 so you still have a ways to go to be the strongest I’ve dealt with.
I’m not sure what measurement you’re referring to that is between 2 and 5 mm.  Based on the little bit you’ve provided here I don’t see any issue with the Shamir Auto III lens for you.  the VSP Unity coatings are fine, but I do think there are better choices.  The Shamir lens is compatible with Crizal Sapphire, which has the best light transmission on the market.
The glare issues you’re referring to are probably because the lens was rolled as well as polished.  The rolling can make the edge look thinner from the side view, but it increases internal reflections rather dramatically.  To minimize the amount of ringing, you probably want to avoid the roll and polish.  I prefer to never polish my lenses because it does negatively impact the optics.  Generally speaking the satin polish does improve cosmetics though.  Transitions Signature really works pretty great now.  I think your color choices will be limited to grey only in a 1.74 but that’s not necessarily a bad thing.  You can also get Graphite Green and Brown in 1.67.
If you do a Varilux digital progressive (think X Design, Physio DRX, etc.) you will get additional blue light protection as well.

PS- I don’t wish to countermand the recommendations of the doctors and opticians out there.  They are always going to be more deeply familiar with the prescription, frame and lens fit of the patient than I will (unless they come see me).  But based on the information provided, these would be my recommendations.  Knowing specifics of frame fit (i.e. actually seeing how it sits on the face) can sometimes change what my recommendations might be.

If you’d like to contact me for you own piece of Correspondence, please feel free to shoot me an email!

A Piece of Correspondence

Today, I received an email from a reader, and with his permission, I am sharing it here.  I think the questions raised are excellent, and could  be quite helpful to some of you other readers out there!

The Message & Response
My Responses are set aside by color and italics

Dear Optical Jedi:

I have a “heavy” prescription. In September 2005…I chose [a smaller frame] to be better for my prescription, at least in terms of weight, minimizing the “Coke bottle” effect, etc.

In September 2005, my prescription was
OD -7.25 = -1.00 x 180
OS -7.75 = -2.00 x 160
add +2.25

I have an eye exam scheduled for early October, and I’m confident I’ll need new lenses, if only because of further deterioration in my near vision.

I’ve worn progressives for nearly 30 years, and never had any adaptation problems. I started with Varilux Comfort. I switched to the Ipseo because I was advised I’d see a substantial improvement in my vision and experience [pun intended].

Opticians at three different practices have said, without any guarantee, that my Lindbergs may be reused again. Accordingly, I’m looking for:
* new lenses for my Lindberg frame, which I’ll buy with my FSA; and
* backup and sunglasses via my Davis Vision benefit.

Davis, I’ve been told, offers the Shamir InTouch and MyFocal HD as its “ultra” progressives the Varilux Physio and Zeiss GT2, among others, as its “premium” progressives.

The three opticians I’ve visited all want to keep me with Varilux, although I’m willing to change companies, if either I can get something likely to work better for me, or I can get substantially the same functionality for less.

For my primary pair, two of the three opticians recommend the Physio W3+ Fit. One recommends the “S”; the other two advise against it (and say my price would be the same for the W3+, the W3+ Fit, or the S.) The “X” is not recommended primarily because of lack of either personal or customer experience. No one has mentioned the Physio DRX, which you recommend for myopes.

Before getting to some specific questions, I should add that I’m nearly 68 and work in a professional environment. Most of my work time is spent either using a computer or at meetings. I drive to and from work. I do spend time outdoors on weekends, see movies and plays, etc., but that’s not my primary focus.

So, here are some questions I’d appreciate help thinking through:

1. Is it reasonable to combine more advanced primary lenses with older technology sunglasses and backup glasses?
I have seen some patients have difficulty with this, but if you had no trouble switching lens designs in the past, I seriously doubt you will have any concerns.  I tend to use a primiary design for most of my glasses, but I do switch designs (i.e. Maui Jim cannot use a Varilux design) and have very little difficulty with it.  Sometimes there can be a momentary adjustment as your eye adjusts to a new design, but it shouldn’t last more than a couple of moments.

2. If so, and considering the limited selection from Davis Vision, what reasons are there, if any, to consider switching from Varilux to Shamir?
I’m sorry you have Davis Vision.  There limited formulary is one of the most frustrating aspects of fitting a Presbyope.  As a rule, Shamir works very well.  They created the original molds of designs going back 40-60 years ago, that were used for companies such as Varilux.  I have no personal wearing experience with the Shamirs offered by Davis, but their lens tend to be very comfortable.  Before the advent of the X Design from Varilux I would say that the Autograph II from Shamir was probably my favorite design to wear.

3. Why would it be inadvisable, if it would be, to choose different brands for my primary lenses and Davis Vision lenses?
Again, it’s not necessarily a problem, but the greater the difference in technology between designs, the harder it is to “code switch.”  For example, if you were to mix a budget solution like an Essilor Ovation, with an X Design, you would probably find it very jarring and difficult.  Specifically the behavior in the near and mid-range zones are quite different and you would do more hunting for your reading zone in the basic design.

3. Put otherwise, what can you say for my general situation about (a) Physio v. MyFocal; and (b) Varilux [W3+, W3+ Fit, Physio DRX, “X,” ?] v. Shamir III or II (your Shamir recommendation in your blog article)?
The amount of astigmatism correction you have starts to creep up in importance of design choice.  The Physio is honestly not something I would call premium and it frustrates me that Davis categorizes it so.  Physio is not a bad lens, but the edges of the clear zones are more “canyon-like” and you drift into the blurry distortion zones faster (i.e. you’ll need to point your nose more).  I personally did not care for the W3+ for myself.  I have a -3.50 Rx with a +1.75 add.  I found it a little tight and frustrating.  The DRX is generally more comfrotable for a Myope, as you’ve noted that I recommend.  The biggest variable for that recommendation is just how close the frame sits to your eyes.  If you have a longer vertex distance, it can cause more frustration with narrowing your fields.  You should be quite comfortable wearing both Shamir designs with no difficulty.

4. How significant is the difference likely to be for me between 1.67 and 1.74? Relatedly, when Varilux’s availability chart says that an A/R coating is “systematic” with the 1.74 lenses, does this mean that the cost is built in to the price of the lens or that, if I buy a 1.74 lens, I have to but one of the Crizal coatings?
I have a calculator available to me which allows me to see rather specifically the differences in thickness based on Rx, frame, and fitting measurements.  Doing a rough estimate of frame size and PD measurement, you would see approximately a .6 mm edge thickness difference going to a 1.74 hi index.  But, there can be significant concerns with 1.74 and grooving for a Corona frame.  Lindberg specifically recommends 1.67 for their frames because of its tensile strength.  It can handle the grooving better.  The reference to systematic is indicating that 1.74 cannot be purchased without including a Crizal Alize or better coating.  You still have to pay for the coating as well, but given the light loss inherent in the thinner material, the coating is required to guarantee quality of vision.

Finally, I’d add that given your Rx, lifestyle, and other notes you have given me, I think that the Crizal Sapphire 360 would be an extremely wise choice for you.   If you were to switch frames to a full framed/non-grooved model I would suggest switching to the 1.74 to minimize thickness, but in the lindbeg I would stay in 1.67.  I also think you’re probably a very good candidate for Transitions Signature.

I suggest the Shamir II mostly because it’s the one I’ve worn and I know it’s good.  I’ve heard positive feedback from friends in the industry regarding the Shamir Autograph III, but I don’t have the personal experience to add to it.  My understanding is that the zones are wider.  

Between a Varilux S and a Varilux X it’s quantitatively different.  I’m not a very big fan of the S and how it performs.  It’s a great lens, but I would not call it the best lens.  The X is the best thing I’ve worn.  It’s a significant improvement in function.  X would be the one I would recommend most strongly for all purposes.  I understand the desire to stay with Varilux.  Once you know a brand and it’s characteristics, it’s easier to work with just that collection.  You won’t see poorly in a Varilux, but the standard Physio is just not as versatile a lens.  If you spend a lot of time in front of a computer you’ll be much happier in an X Design, or a Shamir Autograph (either II or III).  Again, I don’t have personal experience with the MyFocal so I can’t be too specific on what to expect with it, but it is lower down the scale of the Shamir products from the Autograph series.

The big differences in the X Design versus other lens choices is that the width of the field for midrange and near is significantly larger (almost the full width of the lens), and the depth of field in each zone is more significant.  So, for example in the bottom “near” zone you can stretch out to arms length away.

Take Away

I am here to answer questions.  Sometimes that’s from my posts, but it can also be from your directed questions for me.  If you have anything you’d like me to tackle, on a personal note or not, please feel free to email me opticalric@gmail.com and of course you can always reach out to my Facebook and Twitter handles too.

3D Glasses. How Do They Work Anyway?

My recent piece, describing the difference between polarized and tinted sunglasses inspired me to address 3D glasses, since they also use polarization to work. Yes, you read that right. The same polarizing technology which reduces glare when you’re driving, also allows you to see an extra dimension at the movie theater.

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As you might recall, in my last post on sunglasses, polarized glasses work by having a film sandwiched inside the lens which only allows wavelengths of light to pass through on one plane. 3D movie glasses are using a polarizing film (with no corrective lens around it, and that’s why they are so thin), but their film is doing something quite different. RealD is the most commonly used three dimensional movie projection system. And they use a circular polarizing film. So, in other words, instead of letting light through on a plane, it’s letting it through on a circle. This allows them to “wink” the image constantly between the two eyes, and not cause shear, or blurriness as you move your head around to get your drink, or eat your popcorn.

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ISSUES WITH 3D

In order to keep costs for the 3D glasses at a minimum, theaters use the polarizing film mounted into a frame, with no ophthalmic quality lens holding it in place. This impacts your vision in a couple of significant ways.

  • First, with no lens to keep the film rigid, there can be waviness or lack of crispness to your viewing experience
  • Secondly, the lenses scratch very easily, so not only are viewing through a lens with poor optical quality, but there are scratches in your way as well.
  • Additionally, if you wear corrective glasses yourself, and put the 3D glasses over them, you can have trouble with comfort on your nose, or even looking through the right part of the lens.
  • Lastly, since these lenses are made as inexpensively as possible, they are very hard to keep clean and the fingerprints can create additional blurriness impeding your experience.

There are solutions for most of these issues for a relatively low cost. There are RealD compatible clip-ons and standard glasses available for purchase from your local optician, or even from online retailers (just do your homework here to make sure you’re getting good quality). Of course, as all of you know, I wear glasses almost exclusively and while I absolutely love going to the movies I have not enjoyed 3D experiences for all of the above reasons. Also, the polar film paired with the less bright projection of a 3D film makes everything dim and washed out. But I found a supplier for these 3D clip-ons and they revolutionized my film going experience. The optical clarity is much better, since the lenses are ophthalmic. Also, the tint of the polarizing film is lighter, so the screen is brighter. No scratches means I can see what I’m watching and there is no additional weight on my nose.

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Excellent clarity with 3D clip-ons

TROUBLES WITH 3D?

There is a segment who cannot view a 3D film without terrible headaches and sometimes even nausea. Because the image is flickering at an incredible rate to alternate the images between the two eyes, this flicker can cause serious problems for those susceptible to migraines. Just as there are clip-ons for 3D, there are also 3D for converting your experience to 2D. Essentially it makes sure that both eyes are getting the same single image. I have found these for RealD at Amazon.

What About IMAX?

IMAX uses a completely different technology and I have yet to find solutions for all of these situations for them. But since my favorite movie theatre, where I do my charity work is IMAX 3D I am working diligently to find solutions!

What are Polarized Sunglasses?

I have found throughout my many years in this industry that many patients still do not have a clear understanding of the difference between a tinted and a polarized sunglass. So, the big question you’re probably asking yourself is, “why do I want over another?”
For the vasty majority of patients, the polarized makes more sense. I hope to explain why here.

Tinted Vs. Polarized – Why one over the other?

The two ways a sunglass lens can be created are vastly different. Tinting is perhaps a bit more straight forward and easier to understand, so I’ll address this first.

When tinting a lens, we start with a perfectly clear lens, and dip it into a hot dye until we get to the color, density, and pattern you desire. The advantage on a tinted lens is that it can be as dark or as light as you’d like. It can be gradient or solid, and it can be pretty much any color under the rainbow (including having mixes of color).

TintedGradient

Gradient Tinted lenses

Based on the above, it sounds like a tinted sun lens is the smartest way to approach it, right? I mean, why discuss anything else??

But what does tinting do for glare? That is the question…and that question is answered with polarized lenses.

Polarized lenses are created in a completely different fashion. There is actually a film sandwiched inside the clear lens (for most versions of polarized…see Maui Jim below). This film is actually made of thousands of microscopic lines packed so closely together they give the appearance of color. These lines are placed so closely together to handle the glare.

polardemo

microscopic lines in a polarizing film removed out-of-phase wavelengths of light

How Polarized Works

Polarized lens technology takes advantage of the wave nature of light. When light reaches us from the sun, it folows a unifom wave pattern, wherein all the light is in phase–that is to say all the wavelengths of light are in the same plane. When the light hits a surface, it scatters in multiples angles, creating the flare of glare.  This is where the polarized film in your sunglasses comes in.  All those lines, packed so tightly together, prevent all the scattered light from passing through the lens.  Only the original wavelengths, continuing in their original straight path, are let through.  This dramatically reduced the reflected glare and increases visual comfort, even on a lens with less tint.

Sounds great right?  You must be asking yourself, “Whats the catch?” Well, I wouldn’t call it a catch, but there are a couple of things to be aware of with polarized lenses.  LCD displays use polarized film to work.  When two polarizing films are set 90 degrees apart, all visibility is blacked out.  So this means, if you look at a digital calculator, as an example, it could be black and impossible to see any image displayed.  This is rare, and can be fixed by tilting your head slightly.  In my experience, there can be issues with clarity on the LCD displays for some cars (i.e. BMW’s from the early 2000’s).  This can include your odometer or even your GPS navigation system.  Pretty much all smart phones post version 5 (iPhone, Galaxy) this is a non issue.  But the older devices can have a soap bubble appearance.

Is Polarized Right for You?

For the vast majority of patients, Polarized lenses will be more comfortable and functional. But there are some lifestyles, and work environments where polarized lenses don’t make a lot of sense.

  • Pilots: you’d think this was a perfect case for polarized making sense, but the Shatter resistant windscreens of planes can create tremendous rainbow distortions which are only clearly visible when looking through a polarized lens.
  • Photographers:  The viewfinder on most SLR and DSLR cameras are LCD, which can have terrible rainbow distortions when viewed through a polarized lens (think of the earlier example of soap bubbles).
LCDPolar

LCD through Polar

Maui Jim polarized lenses are a little different in that their polarizing film is fused directly into the lens so delamination is a non-issue and colors are enhanced in a substantial way.  I have worn polarized lenses from at least a half dozen lens manufacturers and I always fall back on Maui Jim’s as my go-to pair–even when the prescription is out of date.

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Take Away

Polarized lenses dramatically reduced your perception of reflected light/glare while wearing them.  The technology does allow you to see chromatic structures and other things not normally visible with the naked eye.  This is less of a problem, than something to be aware of, and to know how to get around it.  While polarized lenses make the most sense for most patients, there are subsets of the population where polarized just doesn’t make sense, such as photographers and pilots.

UPDATE

A couple of comments I’ve received led to this note. Since there is an angle to the Way polar film removes glare, both eyes must be on the same angle, or plane. If they are off, they can give you a very odd sensation. In fact, 3D glasses work by having the polar film at 90 degree angle to each other, giving each eye a different image to create the 3D effect. If you have inexpensive sunglasses you can sometimes get this experience.


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