For the
estimated 30 million Americans suffering from dry eye, the initial diagnosis is
often the biggest barrier to experiencing relief. In a world where spending 9+
hours a day on screens and devices is considered normal (1/3
of Americans do!), we can often normalize our ocular discomfort as just “being
tired.” But redness, watering, fluctuating vision, and eye fatigue are signals
of a much more serious underlying medical condition. Dry eye isn’t just uncomfortable eyes –
it’s a progressive inflammatory condition that can result in permanent
structural damage and even vision loss. The initial diagnosis is key to getting
treatment to prevent severe damage to the ocular tissue.
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| Dr. Lyerly spends a lot of time talking about meibomian gland disease in her practice. |
Where to look first?
Since
the 1980s, there has been an abundance of research and evidence showing
that dry eye often begins at the level of the meibomian gland. In fact an estimated
86% of people diagnosed with dry eye have underlying Meibomian Gland Dysfunction. Every human has around 20 glands in their inferior eyelid and
30 in their upper eyelid that secrete tear film oil (called meibum) onto the
surface of the eye with each blink.
These glands produce the top layer of the tear film, the important oil
layer that holds the tear film onto the surface of the eye to prevent watering
and evaporation. If the meibomian gland secretion becomes blocked or irregular, tear
film evaporates at a much faster rate, causing eyes to burn, water, and vision
to fluctuate. But more importantly (and
detrimentally), the body’s own protective feedback loop to prevent dry eye
is initiated. If the corneal nerves
sense that the eye is too dry, they send feedback to the lacrimal and meibomian glands
to produce more tear film. But if the
glands are blocked or obstructed, no matter how much tear film gets produced,
nothing can be secreted when the person blinks. The result is inflammation: the
glands are hyperactive to try to overproduce missing tear film, but no relief
occurs, so more hyperactivity is turned on.
It’s a devastating feedback circle that can result in a persistent cycle
of worsening pain, redness, and blurry vision.
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| The yellowish circles here are the meibomian glands of the superior eyelid. Inflammation is clearly evident in my patient; the lid margin is very injected (red) - a hallmark of chronic dry eye. |
Detecting
Meibomian Gland Dysfunction
How does
your doctor discover underlying problems with your Meibomian glands? We have a
variety of techniques and diagnostic devices to help us find early signs before the patient may even experience
any symptoms, which is of course the best time to intervene!
“Not every patient who presents with dry eye or meibomian gland
dysfunction is symptomatic. Typically, however, patients will notice some
occasional foreign body sensation, irritation, redness, blurred, or fluctuating
vision,” says Dr. Christine Wisecarver of See
Clearly Vision. In addition to just asking about symptoms, doctors may also
use questionnaires like the Ocular Surface Disease Index (OSDI) or Standard Patient Evaluation of Eye Dryness(SPEED). These surveys are designed to unlock dry eye complaints that
may be passed off by the patient as “normal” and thus underreported when the
doctor directly asks.
Dr.
Leslie O’Dell of Mechanicsburg Eye
also recommends asking patients about specific activities and times of their day to unlock
possible meibomian gland dysfunction-related symptoms. She
asks patients how their eyes feel in the morning when they wake up – AM watering
or burning could be associated with inflammatory eyelid conditions like
blepharitis or demodex mites, or not fully closing the eyes when we sleep
(called lagophthalmos). Another useful question is asking about how eyes feel
after being on the computer for several hours. The
average person blinks 50% less often when looking at screens, which results
in less meibomian gland expression (the glands only secrete when we blink). Blinking less can have a devastating toll on the glands as it can also result in higher incidence of clogged glands. If oil
stays in the gland too long it can begin to harder and obstruct, eventually choking the gland off from nutrients and causing gland atrophy and death.
Symptoms
of watering are extremely common indicators of dry eye. “When our technicians meet with patients who present with dry eye,
and their main complaint is excessive tearing, the patient is extremely confused
to hear they have dry eye,” states Dr. Wisecarver. “WE must explain that the
tear film is made up of three different parts. If the eye isn't producing all
three parts in the correct proportions, your eye will over produce others, thus
causing excessive tearing.”
Blurry vision is another indicative
complaint Dr. Wisecarver sees in her dry eye practice. “Some patients also have
the misconception that their blurred vision means they simply need to change
their glasses prescription. We often explain that blurred vision may not be a
prescription change but rather a consequence of an unstable tear film or other
ocular disorder.”
In the
Microscope
Physically
assessing the glands at the microscope is an essential way for doctors to
detect early signs of dry eye disease. “Clinically, we look for blocked, or capped, glands, thickened and red
lid margins, and dilated blood vessels at the lid margin. The doctor will often
gently press on the lids to see the consistency of the oil secretion,” states
Dr. Wisecarver.
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| Evaluating the meibomian glands with the Korb Meibomian Gland Evaluator via |
The key to evaluating meibomian gland
expression is gentle pressure. Our blink offers only a minimal amount of
force on the glands, but a doctor using their finger to manually push on the gland to
determine expression can falsely indicate the glands are working better than
they really are. Meibomian gland guru
Dr. Donald Korb invented the Korb
Meibomian Gland Evaluator to prevent this issue. The device uses the exact amount of pressure
a blink would naturally put on the gland to prevent overestimating expression. There
is much debate within eyecare about the potential dangers of manually and
forcefully expressing the glands (could it damage the glands or cause increased
gland inflammation?), so using this gentle gland evaluation method is
preferred.
There are also great tools to visibly
evaluate the length of the meibomian gland. Gland dilation and shortening (or
atrophy) is evidence of advanced disease, so observing damaged and dying glands
requires immediate intervention. Doctors can use a transilluminator held to the
eyelid skin to visibly see the glands to evaluate length and regularity, or
higher tech imaging systems that can show the glands in all of their subtle detail.
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| A doctor uses a transilluminator to see the meibomian glands. To do this, turn the slit lamp and room lights off, place the transillumintor on the bottom eyelid and gently evert the lower lid. via |
Imaging systems offer a great tool for both the doctor and the patient to be able to see damaged meibomian glands. The LipiView imaging system uses infrared light to highlight the glands (below). Also available is the Oculus Keratograph with its Meibo-Scan software.
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| The LipiView system by TearScience is the method used where Dr. Lyerly practices, Triangle Visions Optometry. The patient pictured here is in her 20s and unable to wear contact lenses anymore due to dry eye and fluctuating vision with lenses. |
Take Home
Once the doctor diagnoses Meibomian gland
disease, the most important thing for the patient is to understand is that dead
and damaged glands is not normal – it’s a sign of advanced disease that can
result in permanent discomfort and visual distortion. Waiting to intervene will
only worsen the severity of the disease, so there is no better time to start
treating the eyes than when minimal or even no symptoms yet exist.
“MGD is
a chronic condition,” states Dr. Wisecarver. “We are able to improve the
function of the meibomian glands, but not necessarily reverse damage that has
already been done through years of gland blockage. Treatment will reduce
symptoms but consistency is key to managing the problem and preventing the long
term damage.”
“Ultimately, educating patients as to
WHY we recommend following a certain protocol for treatment will encourage the
patient to continue with the regimen. Just like dentistry, you get cavities if you
don't brush your teeth well. However, if you brush your teeth, your risk of
decay is greatly reduced. Similarly, treating MGD daily reduces a patient's
risk of styes, dry eye and damage to the oil glands themselves.”
Whether treatment includes
heating the glands to remove obstruction with Lipiflow, daily heated Bruder masks, eyelid
hygiene, nutritional
supplements, or medication,
daily maintenance is key to preventing worsening ocular health, comfort, and
vision.
A big thanks to Irina Price and Dr. Christine Wisecarver for contributing on this post!
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