Dry eye diagnostics: A simple approach and shopping list
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There has certainly been a whole bunch of new stuff around the dry eye disease ranch, hasn’t there?
For a disease state we have known about for decades, it is almost as if we are rediscovering it all over again. After literally decades without any change in how we think about dry eye disease (DED), let alone how we treat it, now we have new data, ideas and real stuff arriving weekly.
Think for a moment about the basic disease state of DED and the associated disease states that contribute to or complicate both the diagnosis and treatment of DED. Where once we viewed dry eye in the simplest of terms — dryness equaled insufficient tear volume — we now know that a supermajority of DED includes some component of evaporation. Until September, this realization led to more frustration because we had nothing in our quiver to directly treat evaporation. Now we have Miebo (perfluorohexyloctane ophthalmic solution, Bausch + Lomb).
Or ponder how our understanding of the various lid afflictions that contribute to meibomian gland dysfunction (MGD) has evolved. For years we have been stymied, stuck in diagnostic and treatment paradigms that have not changed since 2012 or so. Blepharitis was a single, omnibus diagnosis that we broadly associated with the toxic effects of staph species overgrowth. State-of-the-art treatment pre-2010 meant insisting your patient use Johnson’s Baby Shampoo rather than “generic.”
Five developments arrived nearly simultaneously and rapidly changed our approach: meibography, thermal/expressive treatment, light-based therapy, omega-3 supplementation and AzaSite (azithromycin ophthalmic solution, Thea). Since the early 20-teens, nothing really changed. We continued to struggle with recalcitrant MGD and therefore DED. The missing link, of course, was Demodex. Tarsus has taught us to “look down” and make the diagnosis of Demodex blepharitis, and now we push through a majority of our MGD roadblocks by treating with Xdemvy (lotilaner ophthalmic solution 0.25%).
Which leaves every eye doctor to ponder why and how they will address DED in their practice. Seriously, DED has a deleterious effect on outcomes in every type of eye care practice. Kind of like my declaration that we are all “red eye” doctors some years ago, I think it is completely accurate and wholly appropriate to declare that, like it or not, we are all DED doctors now. Everything starts with making the diagnosis. Here are a few examples of how different types of practices can address diagnosis with available technology.
Trying to pick and choose among the cornucopia of instruments now on the market is as daunting a task as deciding what wine to serve with your holiday turkey: There are just too many options across too many price points, even without accounting for taste. On top of that, just as every kitchen already has a bottle or two lying around (and maybe even a wine cellar), every office already has diagnostic equipment that may be useful in DED. I will try to make it simple for you: three general types of practice and three instruments that will fit the bill, alone or in combination.
To make things even easier, I will concentrate on anterior segment practices led by either MDs or ODs. Not that you retina guys and gals are off the hook. Uh-uh. You just have no need for any equipment that is dedicated to diagnosing DED. All you have to do is have your bazillions of IV injection patients look down and consider treating everyone with Demodex blepharitis.
The easiest practices to address are those that are primarily cataract/refractive surgery practices. Face it, this really means cataract practices. Once upon a time, we all thought that we were going to be super busy LASIK/PRK/SMILE surgeons like Lou Probst or Michael Coleman. With the exception of acts of God (see: Marguerite McDonald, Hurricane Katrina), most of us have chosen to deemphasize refractive lasers; we got so busy doing “premium” cataract surgery that we mostly do laser vision correction to touch up our refractive cataract results or as a kind of professional hobby.
Regardless, the cataract/refractive practice simply cannot afford to miss the diagnosis of DED. Once again, a hat tip to Eric Donnenfeld: If you diagnose dry eye preoperatively, it is the patient’s problem; make the first diagnosis of DED postop, and it is your problem. To not run afoul of Donnenfeld’s Law, all you need to add to your preop regimen is tear osmolarity.
All it takes is a single Trukera ScoutPro in the pocket of each workup tech, and your ability to diagnose DED skyrockets. Elevated tear osmolarity (higher than 308 mOsmo/L) or inter-eye asymmetry (higher than 8 mOsmo/L) and you have your prompt to look harder for the insidious effects of DED on preop measurements. Flummoxed by a 20/20 unhappy result postop? Trukera has recently published data showing that elevated tear osmolarity is associated with light scattering that is equivalent to what we see in a 2+ nuclear sclerotic cataract. Twenty to 30 seconds of tech time doing a test that more than covers its cost. QED.
Practice type No. 2: You are a wannabe DED practice or an established DED practice looking to streamline your workup. It goes without saying that if you are a comprehensive DED practice, you should be measuring tear osmolarity; the one ScoutPro/workup tech applies. Beyond that, the minimum testing you must be able to do is meibography and some sort of topography or other objective analysis of the ocular surface. Anything else that can be automated and simply presented to the doctor will make your workup/visit more efficient.
Enter the Bruder Ocular Surface Analyzer (BOSA), which is scheduled to be released in 2024. To shorten our standard DED visits and improve our overall efficiency, we are adding a BOSA to our diagnostic array at SkyVision. Depending on your choice of specific tests, the BOSA will give you objective measurements of tear meniscus, lipid levels, fluorescein staining, bulbar erythema, tear breakup time and meibography, all in 15 to 30 seconds per eye. If memory serves, you can also document Demodex presence and blepharitis severity, both of which will aid you and your staff when you explain your diagnosis and treatment plan.
Finally, let me suggest an incredibly sophisticated diagnostic instrument for advanced practices, the latest version of iTrace from Tracey Technologies. With the exception of that endangered surgical species that actually does perform lots of laser refractive procedures and needs a Pentacam (Oculus) for ectasia prevention, the rest of us will get all kinds of advanced insights from the iTrace. Objective tear breakup time? Check. Multizone measurement of the effects of dryness on topography? You got it. Want to show your patient how their DED is affecting their vision? Right there on the screen.
And my favorite, the very best measurements of angle kappa (and all the other lesser angles) to help us avoid the ectasia equivalent in refractive cataract surgery, inserting a multifocal IOL of any design where it will not jive with a patient’s line of sight. All with the ability to objectively compare results over time.
There are so many practice types out there and literally enough diagnostic devices available that I once gave an hour-long talk on the subject. Here I have coned it down to three broadly brushed anterior segment practice types, MD or OD led, and three devices that make sense for some or all of them. If you feel the need for a deeper, more comprehensive dive into the world of DED diagnostics, do a search on Omnicuris.com for my name, and you can suffer through an hour of my mug on your screen.
Me? I am asking Santa for an iTrace in my stocking.
- For more information:
- Darrell E. White, MD, of SkyVision Centers in Westlake, Ohio, can be reached at dwhite@healio.com.
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