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December 20, 2021
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Meibomian gland dysfunction and dry eye: The state of diagnosis and treatment today

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With the exception of the eventual, however begrudging, acceptance of dry eye disease as a thing, the biggest paradigm shift in the dry eye world has been the acknowledgement that both tear quality and quantity matter.

Heck, according to the very latest (and best!) definition of dry eye, DEWMD (Doomed), dry eye disease (DED) is “a reduction in the quantity and/or quality of the tears leading to discomfort, visual disturbance or both.” Meibomian gland dysfunction (MGD) of almost any origin is largely the culprit when we talk about tear quality. Michael Lemp, MD, himself is on record as saying that 86% of DED is evaporative dry eye (EDE) associated with MGD.

How, then, should we be treating MGD?

Darrell E. White, MD
Darrell E. White

First, we should spend a moment describing how MGD causes tear film dysfunction. Similar to the pathophysiology taking place on the ocular surface, inflammation on the lid margin and within the glands themselves plays the pivotal role. Inflammation causes the glands to produce thicker secretions. This thickened meibum eventually clogs the glands, a physical effect that is proinflammatory. The meibomian glands then become reservoirs of inflammation, dumping poor-quality meibum laden with inflammatory cytokines into the tear film. This results in a progressive decrease in tear breakup time, accelerated evaporation of tears and, of course, increased inflammation on the ocular surface. Eventually, the combination of inflammation and obstruction leads to frank destruction of the glands.

EDE and MGD are hot topics of late. Pandemic-related lockdowns and stay-at-home orders have stranded people of all ages in front of their screens. Neda Shamie, MD, should be credited with coining the phrase “the multiscreen lifestyle” during the launch of Xiidra (lifitegrast, Novartis); whatever our screen use patterns were before March 2020, they are almost universally greater now. Reduced blink frequency and amplitude lead to greater exposure of the ocular surface and, hence, increased evaporation. And when we do get out and about, we are stricken with MADE, mask-associated dry eye, an entity first described and named by yours truly. Exhaled breath is redirected across the ocular surface, increasing evaporation and — you get the point.

Both MADE and the multiscreen lifestyle are adding insult to injury. Remember those simple days when we thought MGD/blepharitis was caused by staph overgrowth and exotoxins released on the lid surface? That is still a thing. Demodex has been around forever. Got collarettes? If so, you also have Demodex, and the mighty mite is messing up your meibum. A newer cause is the progressive decrease in anti-inflammatory omega fatty acids in our modern diets caused by changes in how our food is created in the developed world. Where once our protein sources ate whatever it was they ate before the industrial revolution, now they are almost universally fed corn. Corn, as you know, is high in pro-inflammatory omega-6 fatty acid and bereft of anti-inflammatory omega fatty acids such as DHA/EPA and GLA.

Call it the effects of “Big Farma.”

There are some pretty sexy new treatments that I will get to in a moment, but we ought not forget the tried and true. Hank Perry, MD, will have my head if I do not give a plug to the liberal use of doxycycline (or minocycline) in MGD and EDE; 50 mg twice a day — cheap, effective and rarely upended by side effects. Equally low on the sexy scale would be heating the eyelids and lid hygiene. I think of these as the “blocking and tackling” of MGD care. No one is winning without them. Until we have a Demodex-specific treatment (come on, Tarsus!), you would do well to suggest a commercial scrub that contains tea tree oil. Up your “at home” game by having your patients use NuLids (NuSight Medical), a more effective way to clean the lid margins. Did I mention nutritional support?

Every patient with MGD/EDE should be taking re-esterified fish oil (we like PRN) or GLA (HydroEye). You should round out your basic treatment with oil-based artificial tears for comfort. Take a stand against the proinflammatory effects of benzalkonium chloride in preserved tears and “prescribe” Refresh Optive Mega-3 (Allergan) or Retaine MGD (OcuSoft). And let us not forget treatments for intermittent symptoms with antibiotic/steroid combination drops and ointments such as the Tobradex/Tobradex ST (tobramycin 0.3%/dexamethasone 0.05% ophthalmic suspension, Eyevance) franchises. Many symptom “flares” are caused by an MGD “dump” of inflamed meibum onto the ocular surface. Kala has done the hard work showing that flares are real; Eysuvis (loteprednol etabonate ophthalmic suspension 0.25%) is FDA approved to treat them.

This is where I am supposed to talk about AzaSite (azithromycin ophthalmic solution, Akorn), but really, I am just too sad and depressed and beaten up about all things AzaSite right now.

On a much brighter side, how about those in-office MGD treatments? Sure, there are the same challenges we face in all cash-pay parts of our world, but there is lots of stuff that just flat-out works. Whether or not you subscribe to the theory that meibomian gland inflammation can be ascribed to a bacterial microfilm, the targeted lid cleaning treatment BlephEx (Alcon) is highly effective in reducing obvious gland obstruction. With or without BlephEx, you can manually express thickened meibum with any number of dedicated instruments.

As we move up the “sexy” scale, in-office direct-to-gland heating treatments are a full order of magnitude more effective than any at-home thermal therapy. If you feel that expression under your direct control is the way to go, you have two options. TearCare (Sight Sciences) allows you to apply heating elements to the skin directly on top of the tarsal plates, after which you use your instrument of choice to manually evacuate the melted secretions. iLux (Alcon) goes one better, heating the conjunctival side of the tarsus before you use the same unit to express the glands. Rumor has it that Alcon is soon to release an upgraded unit that allows the user to observe the surface being treated. More of the “autopilot” sort? The “mack daddy” of thermal/expressive treatments has you covered. With LipiFlow (Johnson & Johnson Vision), the glands are heated on the inside of the lid before base-to-apex directional massage is applied to empty the now liquid secretions.

Last, but most certainly not least, the addition of light-based therapies has been transformative in the treatment of EDE. At present, there are three competing technologies on the market, at least internationally. All of them are based on the science of photobiomodulation (PBM), the use of specific wavelengths of light with various exposure patterns and strength, directed at abnormal tissue. There is a wealth of data on PBM in rehabilitation medicine and wound care. Credit should go to Rolando Toyos, MD, for seeing the results that our dermatology colleagues were enjoying with light therapy and adopting the technology to MGD and EDE.

Intense pulsed light is available in the U.S. via the Optimal Pulse Technology (OPT) in the Lumenis M22. This is the direct descendant of Dr. Toyos’ early work. It has been refined over the years by DED experts such as Laura Periman, MD, and Cynthia Matossian, MD, and is the technology we use at SkyVision. E-Eye from ESW Vision uses a slightly different technology called intense regulated pulsed light. Finally, low-level light therapy (LLLT) with a unit called the Equinox (Marco) has been championed by Karl Stonecipher, MD. Multiple studies of the three technologies have demonstrated that PBM improves all things MGD and EDE, including tear breakup time, Ocular Surface Disease Index and various measures of meibum quality. Karl has shown that LLLT is effective in the treatment of chalazia in children, a particularly challenging problem we all face. Which PBM therapy should you choose for your clinic? This is such a new and complex area that it deserves a deeper dive. Be on the lookout for a series on my blog at Healio/OSN.

And there you have it. The state of MGD and EDE today. Phew! Just wait for all of the cool stuff that was introduced in New Orleans at the American Academy of Ophthalmology meeting to hit the streets. DED remains the “hot dot” of eye care in the U.S.

Editor’s note: On Dec. 21, 2021, the names of omega fatty acids were updated. The editors regret the error.