A macro view of a closed eye showing the lash line and the edge of the eyelid

Meet Your Meibomian Glands: The Oil Glands Behind Most Dry Eye

There are somewhere between twenty-five and forty tiny glands buried in each of your eyelids, and if you have dry eyes there's a good chance they're the reason. They are called meibomian glands. Almost nobody's heard of them, including plenty of people who have been managing dry eye for years.

They are worth understanding, because once you know what they do, most dry eye advice stops sounding arbitrary. The warm compress, the ten minutes, the blinking exercises, the fish oil. All of it points at these glands.

A macro view of an open eye showing the upper and lower lid margins and lash roots

Where they are

Run a fingertip along your lower lash line and press gently. That firm strip you can feel is the tarsal plate, a piece of dense tissue that gives the lid its shape. The glands sit inside it, arranged in a row like the teeth of a comb, each one opening through a tiny pore along the lid margin just behind your lashes.

Every time you blink, the lid squeezes them and a small amount of oil is released onto the edge of your eye.

The anatomy

A cross section through the lower eyelid

Heat from here Lashes Meibomian glands Tarsal plate Muscle and skin Gland openings

Schematic, not to scale. Heat applied at the skin has to travel through skin, muscle and plate before it reaches the glands, which is why a compress needs several minutes to do anything.

What the oil is for

Your tear film isn't just water. It has three layers, and each one fails differently.

Closest to the eye is a thin mucin layer that helps everything else stick to the surface. In the middle sits the watery layer, which is what most people picture when they think of tears. On the outside is a very thin oil layer, and that is the meibomian glands' contribution.

That oil film is the lid on the whole thing. Without it, the watery layer evaporates within seconds of a blink. This is why so many people with dry eye produce plenty of tears and still feel dry, and why watery eyes and dry eyes are so often the same complaint. The eye floods to compensate for a film that will not stay put.

The tear film

Three layers, and the one that goes wrong most

Oil meibomian glands Water lacrimal gland Mucin Eye surface evaporation, when the oil layer is thin Schematic. The oil layer is far thinner in reality than shown here.

What goes wrong

Meibomian oil isn't liquid at room temperature. It is closer to a soft wax, and it only flows properly once it reaches somewhere around 40°C, which is a little above body temperature at the lid surface.

When a gland stops emptying fully, the oil left behind thickens. The opening narrows. Less oil comes out with each blink, so more sits stagnating, and the gland gradually plugs itself. Clinicians call this meibomian gland dysfunction, and it is the most common cause of dry eye.

Left alone for long enough, a blocked gland can shrink and disappear. This is called dropout, it shows up clearly on the infrared imaging optometrists use to photograph the lid, and it doesn't grow back. That is the single most useful reason to take a boring daily routine seriously.

Why blinking matters more than you would guess

The glands empty by being squeezed, and a blink only squeezes properly if the lids fully meet. Reading a screen, most people blink less often and less completely, so a good proportion of blinks don't press the glands at all.

You can feel the difference. Close your eyes as if going to sleep, hold for two seconds, then open. That is a complete blink, and doing a few deliberately every so often is genuinely useful when you have been staring at something.

A woman at a computer rubbing one eye, holding her glasses in the other hand

Signs yours are struggling

  • Eyes that feel gritty or sandy, particularly later in the day
  • Watering that does not relieve the dryness
  • Vision that blurs briefly and clears when you blink
  • Lids that feel heavy, or a lash line that looks thickened or red
  • Recurrent styes, which are blocked glands that got infected
  • Contact lenses that used to be comfortable and are not any more

What actually helps

Heat, held long enough to arrive. This is where most people go wrong. A flannel is below useful temperature within about two minutes, and heat takes four to six minutes to travel through the lid to the glands. The flannel is cold by the time it would have mattered. Whatever you use has to hold its temperature, not just start warm.

A woman holding the Peep Club Heated Eye Wand LED+ against her closed eye, the display reading 37°C

A heated wand holds a set temperature for the whole session, so the warmth is still there at the point it reaches the glands.

Something to move the oil afterwards. Heat softens the plug, gentle pressure along the lid pushes it out. Warmth alone leaves the softened oil where it was.

Keeping the openings clear. The pores sit right at the lash line, which is also where makeup, debris and bacteria collect. Cleaning the margin, rather than the skin above it, keeps the exits open.

Consistency. Glands that have been sluggish for years don't recover in a week. Most people notice something after two to three weeks of daily effort, and lose it again within a fortnight of stopping.

Questions people ask

How many do I have?
Roughly twenty-five to forty in each upper lid and slightly fewer in each lower.

Can blocked glands recover?
Blocked ones often can. Glands that have already dropped out don't come back, which is the argument for acting early.

How do I know if mine are blocked?
An optometrist can press along the lid and see what comes out, and many now have meibography to photograph the glands directly. It's quick, and it turns a guess into a picture.

Do omega supplements help?
The evidence is mixed and they are a slow lever at best. They aren't a substitute for heat and expression.

Is this the same as blepharitis?
Related. Posterior blepharitis is inflammation of these glands. Anterior blepharitis affects the lash line in front of them. Plenty of people have both.

The short version

A row of small oil glands inside each eyelid produces the outer layer of your tear film. When they block, tears evaporate too fast and eyes feel dry however much they water. Heat that actually reaches them, pressure to clear them, and a clean lid margin are what keep them working. Left long enough, they can be lost for good, and that is the part worth acting on.

Sources

General information rather than a diagnosis. If your eyes are persistently uncomfortable, an optometrist can look at the glands directly.

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