What Is Meibomian Gland Dysfunction and What Role Does It Play In Dry Eye?
The term “meibomian gland dysfunction” (MGD) was first introduced by Drs. James McCulley and George Sciallis in 1977, and again by Drs. Donald Korb and Antonio Henriquez in 1980, but gained national attention in the last decade thanks to TearScience’s line of medical equipment that allows eye care professionals to actively and systematically assess gland function, image glands, and treat MGD using LipiScan®, LipiView® II, Meibomian Gland Evaluator (MGE), and LipiFlow®.
The International Workshop on Meibomian Gland Dysfunction (MGD) defines MGD as “a chronic, diffuse abnormality of the meibomian glands, commonly characterized by terminal duct obstruction and/or qualitative/quantitative changes in the glandular secretion. It may result in alteration of the tear film, symptoms of eye irritation, clinically apparent inflammation, and ocular surface disease.”2 It’s also important to note that MGD is both chronic and progressive in nature.
Meibomian glands are a sebaceous gland that contains a grape-like cluster of individual acini that secrete the oil product meibum, which includes lipids and proteins. Understanding the lipid pattern and composition is conceivably the next phase of research needed to discern meibomian gland dysfunction and a critical piece in testing for non-obvious meibomian gland dysfunction and early treatment. Meibomian glands are holocrine glands, meaning the cell is destroyed and excretions include dead cell fragments. Because the acini cells are constantly having to regenerate, discovering what inhibits this regeneration is vital to understanding meibomian gland dysfunction. While the upper lid (25-40) has more meibomian glands than the lower lid (20-30); their relative functional contribution has yet to be determined.3
- Demographics: geriatrics, women, Asian
- Systemic conditions: Lupus, RA, Sjögren’s syndrome, etc
- Ophthalmic Surgery
MGD is a multifactorial condition with many causes contributing to atrophy and changes secondary to gland obstruction. Not all the causes are fully understood and more are being hypothesized and researched. We do know that older patients, women, and patients of East Asian descent may be at greater risk for meibomian gland dysfunction.3
Hormonal changes also affect the meibomian gland production as the nerves are affected by androgens, estrogens, and growth factors. Inflammatory systemic conditions like Rosacea, Rheumatoid Arthritis (RA), Lupus, and Sjögren’s syndrome have been linked with MGD. Some medications, such as Accutane and topical glaucoma medications, have been associated with gland changes and atrophy.3 Environmental factors are linked to meibomian gland dysfunction, especially the misuse of eyeliner and make-up. Other environmental factors include long duration of screen use or high cognitive demand tasks and consequently decreased or incomplete blinking. There are some studies that show extended or daily wear, non-daily-disposable, contact lenses are linked to meibomian gland atrophy.12 More research is needed to assess to what extent if contact lens wearers are at increased risk for meibomian gland dysfunction. Iatrogenic dry eye after ophthalmic surgeries have been linked to meibomian gland dysfunction as well. The following figure nicely sums up the multifactorial causes and processes of meibomian gland dysfunction.
Signs & Symptoms of Meibomian Gland Dysfunction:
While the symptoms of meibomian gland dysfunction are similar amongst many dry eye patients; redness, dryness, burning, grittiness, intermittent blurry vision, and foreign body sensation, the signs are where we can differentiate and diagnose MGD from other causes of dry eye syndrome. In one study, research from Lemp et al9 showed that as many as 86% of patients with dry eyes have MGD, while another study by Korb and Blackie showed that as many as 39% of asymptomatic patients had MGD!4
What Is TearScience?
TearScience was founded in 2005 by Dr. Donald Korb and Tim Willis as a medical device manufacturer committed to providing solutions for eye care professionals (ECPs) to treat meibomian gland dysfunction and evaluate meibomian gland health. In 2009, the LipiView® system was launched and in 2011 the LipiFlow® system was launched.
LipiView® functions to capture lipid layer thickness and blink analysis, and LipiFlow® provides treatment for evaporative dry eye by liquefying and evacuating meibomian gland obstructions. LipiView® II was introduced by TearScience in 2014, which provided high definition structural meibomian gland images by utilizing reflected and transilluminated light sources. In 2016, TearScience released a high-definition gland imager called LipiScan®, which allows ECPs to assess meibomian gland structure in a practice setting.
In 2017, TearScience was acquired by Johnson & Johnson Surgical Vision, Inc., joining their growing portfolio of consumer eye health products and services to help them fulfill their commitment to improving and restoring sight for patients worldwide.
How to Evaluate Meibomian Gland Dysfunction By Assessing Structure and Function
The Johnson & Johnson Vision portfolio of products, including LipiScan® and LipiView® II, provides the tools needed to assess structure via meibography. The physician, with the aid of a slit lamp, can grossly check using a transilluminator, but it is helpful for patient education to be able to photographically show patients their glands in high definition. Gland atrophy can be present in the absence of symptoms. LipiScan® and LipiView® II use Dynamic Meibomian Imaging™ (DMI) to provide fast, high-definition images of the meibomian glands with both transillumination and surface illumination images of the meibomian glands.
You can get an image of both lower lids in about 60s with a trained technician using LipiScan®. I only tell my technicians to evaluate the upper glands with lid eversion if there is significant atrophy of the lower lid meibomian glands. By teaching your technicians lid eversion with a cotton tip applicator, they can easily capture both upper and lower lids when needed. With patients in the chair, I start by showing them the meibomian gland atrophy progression chart (Image 1), point to the top, and say “We are looking to assess meibomian gland structural compromise.” I then show them where they fall on the scale from normal to severe. For recording, I will count the number of complete gland atrophy in each eye, as well as estimate the amount of truncation in four categories (0-25%, 25-50%, 50-75%, >75% truncation). I will also note any significant tortuosity or fracturing (gland atrophy in the middle of the gland, which, overall, is less common). It is also important to note any atrophy, which could have been a result from a hordeolum or surgery.
Image 1: Transilluminated View of Meibomian Gland Structural Changes
Assessing Meibomian Gland function:
The two objective clinical tests I always do are Tear Break-Up Time (TBUT) to assess tear film homeostasis and the Meibomian Gland Evaluator™ (MGE) to assess gland function. I usually have the patients back one month after a comprehensive exam to perform these two tests. During the comprehensive exam, I am using more pressure to assess the quality of the meibum on a scale of clear and flowing (0) to opaque and obstructed (4): does it most closely resemble fresh olive oil, thickened/cloudy inspissated oil, honey, or toothpaste? There may also be no secretion at all. During the follow-up visit we will then perform MGE and count how many glands are functioning with normal blink pressure.
Image 2: Clear oil upon expression
Image 3: No oil on expression
MGE applies between 0.8 g/mm2 and 1.2 g/mm2 and mimics the pressure of a deliberate blink.13 The blinking mechanism is the functioning process of how the meibum is secreted. Through pressure and capillary forces, when the eyelids touch and then open, meibum is pulled and expressed from the lid margin orifice. This is why blinking exercises and evaluating the blinking frequency and completeness is crucial. You can evaluate blinking by observation with NaFL right after checking TBUT or with the advanced imaging techniques with LipiView® II which shows you (and the patient) any partial blinking as well as a percentage of partial blinks.11 You can further access the thickness and quality of the meibum lipid layer using LipiView® II.
How Does LipiFlow® Work?
Efficient treatment for MGD has unfortunately been lacking for decades. The traditional warm compress (which for most patients is a warm washcloth, and is even further from effective treatment) was holding back the medical image of optometry. On top of this, patients instructed to use warm compresses are the clearest examples of poor patient compliance. Warm compresses can easily be equated to flossing in that every meibomian gland dysfunction patient should be using them on a regular basis, but few, if any, do. While the original method of individual manual gland expression, with a paddle or equivalent tool, might also work, it can be extremely uncomfortable for the patient, and difficult for the doctor to execute, greatly limiting its repeatability when it comes to treatment. The fact that meibum re-solidifies in about 30 seconds after liquefaction shows why the procedure can be painful and ineffective. Lastly, manual expression is time consuming and very difficult to perform on the upper lids due to anatomy. Thanks to recent research, revolutionary optometrists like Dr. Donald Korb and Dr. Caroline Blackie, and the FDA clearance of LipiFlow® Vectored Thermal Pulsation treatment in 2011, we finally have a way to efficiently and comfortably treat MGD blockage of both upper and lower eyelids simultaneously! This provides us not only a means to treat symptomatic patients, but proactively identify blocked and atrophied glands in patients who might not yet be symptomatic using LipiScan®, LipiView® II, and the MGE tool.
LipiFlow® is a 12-minute*, in-office, drug-free mechanism of action, automated procedure for the treatment of meibomian gland dysfunction. The automated procedure reduces doctor time to just lid preparation and application of the Activators, while treating all glands, not just ones that can be observed during examination. The device has a small footprint and can easily be moved and stored when not in use. The device uses highly advanced, single-use, sterile Activators that are placed on the patient’s eyes by the doctor and are controlled by the console. Prior to treatment, we recommend an initial numbing drop to improve comfort. LipiFlow® is supported by more than 31 U.S. patents and used around the world as a first line treatment for meibomian gland dysfunction. * Excludes setup time.
LipiFlow® applies just the right amount of heat and pressure to be both safe and effective. LipiFlow®‘s heating element is what makes it stand apart from its competitors. The heat is applied to the inner palpebral conjunctiva, which is closest to the tarsal plate and the home of the meibomian glands, while also insulating the cornea. One of the reasons warm compresses or external heating devices are not effective at getting blocked glands functioning is due to this difference in heat application. External heat has to penetrate through adipose tissue and the orbicularis muscle before reaching the tarsal plate and the meibomian glands.
The device regulates the amount of heat applied and has multiple safeguards that prevent the temperature from exceeding 44 degrees Celsius at the inner eyelid surface. The insulation barrier of the lid warmer limits the maximum temperature at the corneal side of the lid warmer to less than 40 degrees Celsius. This allows to reach the meibum melting point and liquefy it for easy movement. Redundant sensors constantly monitor and control the heat being applied, which is monumental for LipiFlow®’s excellent safety profile and no serious adverse events in pivotal trials.14
LipiFlow® uses pulsed sequences of air to fill the bladders on the upper and lower part of the Activator to express the meibum and stagnant debris in the glands of both eyelids in order to unblock gland orifices. The pressure is constantly monitored to ensure safe levels with an intelligent pressure feedback loop between pressure sensors in the Activators and console. The pressure is applied in a peristaltic, proximal to distal, motion to essentially milk glands, similar to how your esophagus works to safely move a bolus of food from your mouth to your stomach.
A study performed by Dr. Caroline Blackie, et al was designed to determine the sustained effectiveness of a single LipiFlow® procedure and compare it to twice-daily warm compresses through three months (control group). The scientifically validated OSDI questionnaire was used as a subjective measure of improvement and the MGE was used to determine function with a total meibomian gland secretion (MGS) score ranging from 0 to 45, with a score of 45 indicating clear liquid from the 15 lower lid glands evaluated.
With a single LipiFlow® procedure and no other dry eye treatments, there was a statistically significant improvement in both signs and symptoms. OSDI scores dropped (improved) from 44.1 to 21.6 from baseline through 12 months. Also, the MGS score jumped from 6.4 to 17.7 at one month and then was maintained through 12 months. The control group did have some improvement in MGS over 3 months but then reciprocated the LipiFlow® results after LipiFlow® was performed after 3 months of control therapy (crossover treatment group). Symptoms were controlled with a single LipiFlow® procedure in 86% of patients and 89% of crossover patients.
Figure 2: Mean MGS score over time for the 12-month cohort of eyes that received a single Vectored Thermal Pulsation™ treatment.
A newer study published in 2016 showed that there was significant treatment effects from a single LipiFlow® procedure three years after the treatment.6
For those with stubborn dry-eye symptoms after PRK or LASIK, a LipiFlow® procedure improved SPEED II patient questionnaire scores significantly. Using a different method of assessing function, the study also noted improved TBUT (+1.9 seconds), and reduced (better) MGD score and corneal staining.8 (Note: Do not use the LipiFlow® System in patients who have had ocular refractive surgery within prior 3 months)
It should also be noted that the duration and severity of MGD affected the prognosis and outcome of the LipiFlow® procedure, with better results found in those that received earlier treatment or had less severe meibomian gland dysfunction at the time of the LipiFlow® procedure. For these reasons, LipiFlow® is an excellent first line treatment for offices that are proactive in their approach to dry eye care.
Interested In Learning More About Bringing LipiFlow, LipiScan, or LipiView to Your Practice?
We have a direct partnership with Johnson & Johnson Surgical Vision!
Real Cases of LipiFlow® in My Practice
Note: Refer back to Image 1 for normative gland structure.
Case 1: MT
MT is a 48 YOWF that presented to my office for a routine exam. Her secondary complaints revealed epiphora first thing in the morning that sometimes took hours to go away. She tried Refresh Tears™ but didn’t feel like they helped. She stated that her eyes didn’t feel dry, but they had some itch in the morning and afternoon. My exam revealed the following significant findings:
- Epiphora OD>OS
- Good punctal apposition
- Grade 2 Meibum
- Gland engorgement and atrophy
We started daily warm compresses with EyeEco D.E.R.M™ and EZ Tears™ (Omega-3). We discussed LipiFlow® at this visit but had her back for further evaluation since we were accomplishing a routine exam during the initial visit. The follow-up visit revealed:
- (-) Jones Test OU
- MGE: 2-3 glands open OU
- LipiScan® Images (below)
Based on the gland atrophy, truncation, engorgement (i.e structure), patient symptoms, reduced meibum quality, and very low MGE score (function), we determined that LipiFlow® would be the best treatment for her, and she then proceeded with an uneventful procedure.
At our six to eight week LipiFlow® follow-up visit, MT could not have been more happy and her eyes were feeling great. MGE revealed 50-60% of glands were expressing OU (13-15 glands)! She was compliant with the Omega-3 supplements, was doing blinking exercises on occasion, and didn’t feel she needed any artificial tears. We treated some residual allergies and itch with Pazeo® QD PRN and she was on her way. At her yearly exam, MT was still feeling great and had none of her previous symptoms. Below is a testimonial she gave to us after having LipiFlow® done.
“The LipiFlow® has brought immense relief. I no longer feel the burning, and the watering has decreased significantly . It is so nice to not be constantly thinking about my eyes! Thank you for the relief!” – Eyes For Life LipiFlow® patient MT
|Pre-LipiFlow® Treatment||Post-LipiFlow® Treatment|
|2-3 MGE OU||13-15 MGE OU|
POTENTIAL ADVERSE EFFECTS for the LipiFlow® System: Potential adverse effects that may occur as a result of the procedure include, but are not limited to, the onset or increase in:
- Eyelid/eye pain requiring discontinuation of the treatment procedure;
- Eyelid irritation or inflammation (e.g., edema, bruising, blood blister, dermatitis, hordeolum or chalazion);
- Ocular surface irritation or inflammation (e.g., corneal abrasion, conjunctival edema or conjunctival injection (hyperemia)); and
- Ocular symptoms (e.g., burning, stinging, tearing, itching, discharge, redness, foreign body sensation, visual disturbance, sensitivity to light).
SC came to my office for a routine exam with complaints of near vision blur. She is a 51 YOWF who had LASIK in 1999 and then an enhancement in 2002. She stated she has learned to deal with her dry eyes because it has been so long standing. She complained that her eyes were always bloodshot. She had tried punctal plugs 10+ years ago without improvement, and had them removed before our examination. She was taking an SSRI, folic acid, and some vitamins.
On initial examination she had grade 1 meibum through some glands, but the majority of them were non-secreting with thumb pressure. She also had telangiectasia along the lid margins. Her corneas had well-healed LASIK scars. Images taken via LipiScan® can be seen below:
Image 6: Right Eye