Beyond the surface: Tailored solutions for tear evaporation in meibomian gland dysfunction

Image credit: AdobeStock/MyOceanstudio

Expert dry eye specialists Jessilin Quint, OD, MBA, FAAO, from Smart Eye Care, Augusta, Maine, and Selina McGee, OD, FAAO, from BeSpoke Vision, Edmond, Oklahoma, provide comprehensive insights on meibomian gland dysfunction, focusing on its role in causing evaporative dry eye, diagnostic strategies, and effective symptom management techniques during an Optometry Times “Insights” discussion.

Meibomian gland disease (MGD) is a pervasive component of ocular surface disease that is developing in younger and younger patients and is part of dry eye disease (DED). “Rarely do I have a patient with MGD who doesn't have DED,” McGee commented.

She emphasized the importance of discussing MGD with patients in all parts of optometric practices, whether treating the ocular surface, fitting contact and specialty lenses, or with patients considering refractive surgery. When advising patients, she considers the impact of diet, environment, and daily use of multiple electronic devices.

Six factors are potentially involved in causing MGD. Using the BEISTO acronym, these factors are bugs, enzymes, inflammation, stasis, temperature, and obstruction. McGee advises evaluating the eyelids for blepharitis because that can instigate MGD and inflammation. “Once the inflammatory cascade starts with DED, MGD can develop. Patients who are aqueous deficient and patients with Sjögren syndrome…might have started out with healthy meibomian glands early in the disease. However, with persistent inflammation, MGD develops. These go hand in hand.”

Differentiating aqueous-deficient and evaporative dry eye

When faced with both DED and MGD, McGee explained that she uses simple tools, starting with a standardized questionnaire, to help identify DED symptoms. She also presses on the meibomian glands to determine functionality and captures meibography to show and educate the patient.

Her third step is using vital dyes to assess the corneal epithelium. She allows the dyes to set for at least 90 seconds before the slit-lamp examination. She also measures the tear meniscus height for an abnormality. A high value can indicate a drainage problem and epiphora or conjunctivochalasis. If the meniscus height is low, aqueous deficiency is suspected, she explained.

She also noted that patients can have both aqueous deficiency and evaporative dry eye. The data show that 14% of that population has aqueous deficiency and the other 86% has evaporative dry eye. Looking deeper at the 86%, 50% are mixed, and 36% is evaporative dry eye. “The bottom line is that they exist together,” she said.

Long-term consequence of MGD

Quint also emphasized the importance of being proactive in practice by engaging in patient discussions and determining meibomian gland functionality even if the glands look structurally normal. McGee sees opportunities for intervention in these patients before allowing the long-term consequences to take root. If left untreated, the glands will atrophy and die. Meibography is valuable here. “Patients can see that something is wrong. Without treatment, the glands will be permanently lost,” McGee stated.

McGee also discussed the importance of the tear film, the largest refractive component of the visual system. “Without a stable, ocular tear film and functioning meibomian glands, patients will not have good vision for life. It all begins on the ocular surface,” she said.

Because improvements with treatment can progress slowly, Quint related that she uses the speed questionnaire to help patients appreciate improvements in the ocular surface status.

Treatment options

The treatment choice ultimately depends on the stage of the disease progression in the patient. McGee considers MGD, symptoms, and interventional methods to re-establish gland functioning. If a meibomian gland is obstructed completely, it must be unclogged to regain function and flow again. She considers how many glands are functioning, what they can express, and whether others are still viable and need some help. Inflammation on the front surface and tear film status also are considerations, along with lifestyle.

Additionally, McGee inquires about the time of day when the eyes feel worse, ie, upon arising in the morning or as the day progresses. When the eyes worsen over time, the tears are disappearing. Such a patient is a candidate for an intervention to keep the tears on the front surface and prevent evaporation.

The patient’s lifestyle, including diet and use of cosmetics, is a big factor. McGee prefers to use interventional methodologies to reverse the gland obstruction, which involve heat and expression. The interventional mindset is key to long-term treatment. Quint added that most patients need multiple treatments that address the underlying factors causing MGD or DED.

Managing evaporative dry eye

One new tool that was the first FDA-approved treatment for evaporative dry eye is perfluorohexyloctane ophthalmic solution (Miebo; Bausch + Lomb) as the formulation targets evaporation.

“It’s different from anything we've used; the preservative-free, non-water-based drop is 100% perfluorohexyloctane.Miebo embeds itself into the tear film on the ocular surface. This is a 14-hydrocarbon-backed chain that is semifluorinated. Six carbons are attached to fluorine that have some specific mechanisms of action: It is aerophilic on that fluorinated back chain. The other 8 hydrocarbons are highly lipophilic, causing it to bury itself in the tear film. It bobs nicely on the tear film and creates a new surface that prevents our natural tears from evaporating over the course of the day,” McGee said.

Perfluorohexyloctane ophthalmic solution can be used with all other therapies, such as anti-inflammatories and neuro-simulation. An ideal candidate for perfluorohexyloctane is a patient with early disease in a digitally intense work environment, ie, symptoms are starting and their eyes are tired at the end of the day. Other patients who already are on therapy need a way to prevent evaporation, making perfluorohexyloctane a good choice for them as well.

Differentiating between semifluorinated alkane-based therapies for DED

Cyclosporine ophthalmic solution 0.1% (Vevye; Harrow) is another semifluorinated alkane with a different number of carbons. It differs from perfluorohexyloctane, Quint mentioned.

The semifluorinated alkanes are different molecules. Perfluorohexyloctane stays in the tear film for up to 6 hours. Cyclosporine ophthalmic solution 0.1% behaves differently on the front surface: It does not penetrate the cornea or conjunctiva because of the way the molecule behaves. “There always has been frustration with getting cyclosporine into the target tissues, and that's why the vehicles have always been so important. When you consider the gold standard, Restasis (cyclosporine, Allergan), the emulsion facilitated delivery to the tissues,” McGee said.

It’s important to understand the difference between this family of molecules and the semifluorinated alkanes. They behave differently, which is why you would never want to pair cyclosporine with perfluorohexyloctane, because cyclosporine would contain the perfluorohexyloctane on the front surface, preventing the active ingredient from having an effect.

In-home and in-office therapies

Thermal pulsation or intense pulsed light or micro-exfoliation are in-office treatments. McGee uses intense pulsed light to treat patients who have telangiectatic vessels and possibly rosacea. They may benefit from intense pulsed light, which targets those blood vessels that are leaking onto the front ocular surface. Patients with Demodex blepharitis and fmicro-blepharoexfoliation will benefit from an in-office therapy to treat the resultant inflammation. She uses lotilaner ophthalmic solution 0.25% (Xdemvy; Tarsus Pharmaceuticals) for 6 weeks to rid the eyelids of the collarettes.

Patients with obstructed meibomian glands will benefit from expression or thermal pulsation. Some patients with rosacea, MGD, and Demodex blepharitis need all these treatments, but the order of application is important.

“When planning intense pulsed light and blepharoexfoliation with heat and expression, I start with Zocular Eyelid System Technology, followed by intense pulsed light typically for 4 sessions,” she reported. After session 4, she performs heat and expression. The order works well because she first removes some inflammation from the front surface and then heat and expression work better.

In between sessions, McGee favors neurostimulation and anti-evaporative therapy to maintain the front surface with therapeutics in between. She emphasized the importance of educating patients about the between-session treatments, encouraging them to continue the therapeutics, and providing an understanding that this is a process that takes time.

The takeaways

McGee concluded by enumerating a checklist for physicians: adopt an interventional mindset, implement a questionnaire, push on the glands to determine functionality, use vital dyes on every patient, start targeted therapies, and learn as much as possible about the therapeutics and interventions, she advised.

“Treating this patient population requires individualized approaches. We can manage patients for the rest of their lives and give them the best vision for life [because] we have this knowledge now, and we are gifted with the therapeutics and the interventional methods with which we can now manage patients,” McGee concluded.

Interested in watching the video series instead? Find the full conversation here.