Understanding the link between MGD and OSD
Meibomian gland dysfunction (MGD) may be misdiagnosed. While MGD is one of the most common chronic ocular conditions, diagnosing MGD isn’t as simple as it seems.
Atlanta-Meibomian gland dysfunction (MGD) may be misdiagnosed. While MGD is one of the most common chronic ocular conditions, diagnosing MGD isn’t as simple as it seems.
ODs must improve on identifying the differences between dry eye and MGD to effectively treat each disease, says Optometry Times Editorial Advisory Board member Ben Gaddie, OD, FAAO, at SECO 2017.
“There are quite a few people who think that all dry eye is MGD,” says Dr. Gaddie. “That’s too simplistic.”
While inflammation and MGD are separate, they are conditions that often appear together in symptomatic dry eyes.
“They’re actually congruent diseases-they co-exist,” says Dr. Gaddie.
Previously from Greg Hill: Stem cells offering faint cure possibility for glaucoma
MGD components contribute to symptoms
Many patients presenting with dry eye symptoms suffer from a lack of meibomian gland expression. Dr. Gaddie believes that MGD has two primary components:
• Inflammatory
• Evaporative
He says the mucin layer of the eye is a key evaporative component of MGD and dry eye symptoms.
“If you don’t have a pristine mucin layer, you could have evaporation,” says Dr. Gaddie. This evaporative balance is a critical part of tear film quality and eye health overall.
In Dr. Gaddie’s opinion, both of these factors must be addressed during dry eye therapies.
He says that many ODs attempt to manage symptoms by using drugs like Restasis (cyclosporine, Allergan) or managing MGD on its own-but neither strategies alone are enough.
Related: How to know when it’s not dry eye
“If you do only one of the two, you’re going to halfway treat this disease,” says Dr. Gaddie.
MGD and its associated conditions
To understand how to manage MGD, practitioners must understand MGD’s role in ocular health and the associated conditions that it can create.
MGD is a chronic abnormality of the glandular function characterized by terminal duct obstruction. This obstruction changes the quality of the tear film and creates symptoms of eye irritation, clinically apparent inflammation, and ocular surface disease (OSD).
There are various subtypes of MGD. Dr. Gaddie says several classifications of MGD are common in his practice:
• Acne rosacea
• Sebhorriec dermatitis
• Atopic disease
• Psoriatic disease
Dr. Gaddie says certain medications contributed to the severity of these diseases, both in high-delivery MGD and low-delivery MGD. Medications can play a role in low-delivery MGD by reducing the output of the ocular ducts, he says.
“One of the classic things we think of as causing a subacute reduction in the delivery of meibum is Accutane (isotretinoin, Roche),” he says.
Certain drugs may dry the meibum, reducing the delivery of secretions and creating symptoms of dry eye.
Related: How ODs can ease the pain of patient referrals
Managing MGD
While much research has been performed to identify optimal treatments for MGD, Dr. Gaddie says that some treatments may not be effective.
“What do I use to treat? I use heat,” he says.
Warm compresses that help open the meibomian glands can increase secretion flow and clear out obstructions.
Dr. Gaddie says other treatment strategies, including topical drugs such as Zithromax (azithromycin, Pfizer), are an option, but says effectiveness may be limited.
“It works well, but as soon as you stop [usage], the effect goes away,” he says.
Other steroidal/antibiotic drug combinations such as Tobradex ST (tobramycin/ dexamethazone, Alcon) may be useful, though Dr. Gaddie says these medications may have prohibitive side effects.
“Dexamethazone is probably the greatest chance of having an intraocular pressure (IOP) rise,” he says.
But aside from the treatment used to manage symptoms of MGD, Dr. Gaddie says practitioners need to assess all underlying causes, especially blink rates and how incomplete blinks can lead to meibomian gland atrophy.
Related: New research, interest advancing retinal care
“Most patients don’t actually blink fully,” he says.
He estimates that fewer than five percent of his patients have complete blinks. Because of lack of blinking, many people experience weakened meibomian glands that contribute to dry eye symptoms.
Assessing MGD, prioritizing ocular health
ODs must remember that meibomian gland function is foundational to ocular surface health. The ocular surface requires a thorough assessment before treatment begins.
Recognizing when patients have symptoms that should be reviewed is critical. Dr. Gaddie says the SPEED symptom score methodology is one way to quantify symptoms.
“We ask every patient who walks in the door to take the SPEED survey,” he says.
With the SPEED scoring system, a higher score means higher symptom severity.
This strategy helps elicit more information from patients because many patients don’t understand how to articulate their symptoms. Scoring assessments give ODs a different way to assess symptoms.
“It’s been the single best tool to identify patients with ocular surface disease in my practice,” he says.
Related: Gladwell: Health care is a mystery wrapped in a puzzle
The future of MGD treatment
ODs should expect standards of care to change with more priority given to meibomian gland assessment and treatment.
“We will see technologies coming out that allow you to look at the structure of meibomian glands,” says Dr. Gaddie.
While the interconnected nature of MGD symptoms and conditions can make the disease hard to understand, Dr. Gaddie says to take a comprehensive approach to treatment that addresses each dry eye component in turn.
He says his patients who have been on Restasis and LipiFlow (TearScience) treatment have shown the best results.
“The combination of the anti-inflammatory and the gland evacuation seems to be the most productive for patients,” he says.
