Dry Eye   March 6, 2026   •   6 min read

What Is Meibomian Gland Dysfunction? The Hidden Cause of Dry Eye

If you have dry eyes, there's a good chance the root cause is meibomian gland dysfunction — even if you've never heard of it. Here's what it is, how it's diagnosed, and how it's treated at Avalon Eye Care in Vaughan.

The Tear Film Isn't Just Water

Most people imagine their tears as simply water. But your tear film is actually a three-layer structure:

1. Mucin layer (innermost) — produced by goblet cells in the conjunctiva, this sticky layer anchors the tear film to the eye surface
2. Aqueous layer (middle) — the watery layer produced by the lacrimal glands that most people think of as "tears"
3. Lipid layer (outermost) — a thin oil film produced by the meibomian glands that sits on top of the aqueous layer and prevents it from evaporating

If the lipid layer is thin, incomplete, or poor quality, the aqueous layer evaporates far too quickly — leaving the eye surface dry, irritated, and uncomfortable within hours. This is evaporative dry eye, and it accounts for approximately 86% of all dry eye cases.

What Are the Meibomian Glands?

The meibomian glands are tiny oil-producing glands embedded in your eyelids — about 25–40 in each lid. They secrete a specialized oil called meibum with every blink, which forms the lipid layer of the tear film.

In meibomian gland dysfunction (MGD), these glands become partially or fully blocked — often because the meibum thickens and becomes waxy instead of flowing freely. Without adequate oil output, the lipid layer of the tear film thins out or disappears entirely, leading to rapid tear evaporation and chronic dry eye symptoms.

Symptoms of Meibomian Gland Dysfunction

MGD symptoms are identical to general dry eye syndrome — because it IS the most common form of dry eye:

What Causes MGD?

Several factors contribute to meibomian gland dysfunction, and most of us are exposed to multiple risk factors simultaneously:

• Reduced blinking from screen use — blinking is what pumps the meibomian glands. Staring at screens cuts blink rate by up to 60%, leading to gland stagnation
• Age — meibomian gland function naturally declines with age, especially after 40
• Hormonal changes — androgens regulate meibomian gland secretion; menopause causes a significant drop in androgen levels, making post-menopausal women particularly vulnerable
• Contact lens wear — lenses disrupt tear film distribution and can contribute to gland blockage over time
• Certain medications — antihistamines, antidepressants, and retinoids can thicken meibomian secretions
• Rosacea — a skin condition strongly associated with MGD; rosacea around the eyelids (ocular rosacea) is a major risk factor

How Is MGD Diagnosed?

At Avalon Eye Care in Vaughan, we diagnose MGD as part of a comprehensive dry eye assessment. We examine the eyelid margins under a slit lamp, evaluate meibum quality by gently pressing on the glands, and assess tear film stability. In some cases, we can visualize the glands directly.

How Is MGD Treated?

The good news: MGD is very treatable when caught early. Treatment is aimed at unblocking the glands and improving meibum quality:

Can MGD Be Cured?

MGD is a chronic condition — it requires ongoing management rather than a one-time cure. However, with proper treatment most patients achieve excellent symptom control. The key is catching it before the glands suffer permanent damage (called gland dropout), which is why early diagnosis at your annual eye exam matters.

If you've been living with dry, uncomfortable eyes, book a dry eye assessment at Avalon Eye Care in Vaughan. We'll identify whether MGD is the cause and put together a personalized treatment plan.

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Written by the optometrists at Avalon Eye Care, 200 Whitmore Rd Unit 15, Woodbridge (Vaughan), ON.  Back to Eye Care Blog