In the years preceding 2012, the role of meibomian gland dysfunction (MGD) in dry eye disease (DED) was only minimally understood.
Then, researchers Caroline A. Blackie, OD, PhD, and Donald R. Korb, OD, FAAO, published their theories which drew the connection between MGD and DED, forever altering the trajectory of DED treatment.1 They introduced the theory that improving the function of meibomian glands was critical to overcoming obstructive MGD.
Working with Massachusetts Institute of Technology (MIT) engineers, Dr. Korb discovered that the typical melting point of the waxy oils responsible for restricting the glands was between approximately 41 to 42° Celsius (107.6° Fahrenheit). He postulated that achieving this temperature within the glands would permit liquefaction of the meibum and allow for gentle expression, subsequently unclogging the obstructed oils.2
This was the genesis of the modern management of MGD using in-office treatments that utilize radiofrequency (RF) and intense pulsed light (IPL) therapy.
Radiofrequency’s effect on meibomian glands
As one of the early adopters of Dr. Korb’s LipiFlow technology, a technique that delivers heat and vectored pulsation to the affected area, I deduced that there were potential drawbacks to using a computerized, mechanized activator technique, specifically:
- Lack of customization (i.e., the inability to allow more heat in some cases, and a longer treatment time and more expressive force in others).
- Inability to cover a broader area, evident in cases where the activators failed to cover the full length and breadth of some eyelids.
- Some lids could not easily accommodate the bulky activator and could not be treated.
At the same time, I was using monopolar RF as an aesthetic tool, which coincidentally aimed for a similar temperature range to activate the fibroblasts responsible for producing and repairing skin collagen and elastin. By working with thermal imaging cameras to fine-tune the heating over thin, sensitive lids, I was able to match LipiFlow’s heating and expression, which I documented in a pilot study published in the Journal of Dry Eye Disease.3
On label, RF therapy activates cells that help reduce fine lines and wrinkles, while off-label, it helps restore the flow of meibum from the meibomian gland. Until existing RF manufacturing companies complete the US Food and Drug Administration (FDA)-required studies for on-label treatment over the eyelids, RF for managing MGD will remain an off-label treatment.
However, these heating techniques are recommended to be applied solely around the orbit as a means of treating a dry eye patient. This has the effect of helping a patient look younger, although it may not measurably improve the function of obstructed meibomian glands.
Nonetheless, I’ve continued to refine this technique by co-inventing thermaShield (eyeThera), an eye shield specifically designed to assist physicians interested in assisting at mechanized blepharoexfoliation and in using RF energy around eyelids to maximize the ability to simultaneously heat and express the waxy oils.
Monopolar vs. bipolar RF energy
Monopolar RF sends a vibrational “cloud” of energy deep into the tissue. The “ground” for the monopolar energy is a distant “neutral plate,” typically applied to bare skin between the shoulder blades, which allows for a deeper—and more beneficial—flow of energy into the skin.4
Bipolar RF sends a tightly circumscribed “arc” of vibrational energy into the skin. The tip of the arc is generally defined as ½ the distance between the electrodes in the handpiece tip. A grounding plate is not required since the flow can occur only between the two surface electrodes.4
With both monopolar and bipolar RF, the depth, area, and amount of heat—all of which result from the vibration of water molecules within the tissue—are regulated by:4
- Frequency of the RF
- Power/energy used
- Size of electrode used to contact the skin
With monopolar RF, the type of electrode used to contact the skin is also a factor. Whereas, with bipolar RF, the distance between the two electrodes in contact with the skin is an additional determinant.
Of note, it’s the frequency that determines the depth of radiofrequency penetration—with lower frequencies penetrating deeper than higher frequencies. In regions where skin is thicker or the target is deeper, having an option to easily modify the frequency for the desired response is necessary for optimal results.
3 reasons monopolar RF is preferred for ophthalmic treatment
1. Risk of arcing
If the tip of the instrument is disconnected from the skin while power is still being applied, the RF energy flow is interrupted; this may cause an energy arc in which a spark jumps from the tip to the skin.
This arcing is akin to a tiny shock, such as one gets from walking over a wool carpet on a dry winter day and touching a metal doorknob. At higher powers, these arcs can result in focal burns to the skin, although at powers common to eyelid skin treatment, they tend to be more of an annoyance.5
New technologies have evolved to limit the arcing risk in monopolar units, but the “jump” from electrode to skin is difficult to avoid in bipolar technology. You see, the flat plane between the bipolar electrodes is best used over a flat surface; however, the eyelids are rounded to conform to the eyeball beneath.
Unless the handpiece is “rolled” evenly over the lid, it is easy to “tip” the handpiece in a way that breaks contact on one electrode and sends that arc to the skin. Also, the arc (or RF flow zone) from bipolar technology is determined as ½ the distance between the electrodes. This distance is fixed in the handpiece, negating one’s ability to customize the depth of the area being treated.
It should also be noted that the FDA requires an audible signal to indicate when the RF energy in use is interrupted, which can prove to be quite startling—and in the case of one bipolar RF device, this sound is similar to the discordant beep from the “Operation” game popular in the 1970s!
2. Heat regulation
As heat is best regulated at the skin’s surface rather than the subdermal zone, it takes longer to get the deeper portions of the lid uniformly heated—the meibomian glands being a part of that deeper area. The gentle “cloud” of RF energy from monopolar applications permits a more rapid and even heating of that deeper eyelid tissue.
3. Device design
A significant number of bipolar handpieces are designed with the active electrodes embedded in raised ridges on the tip, which can cause the device to drag over loose lid tissue, rather than sliding smoothly.
This makes it more challenging to simultaneously express the melting oils from the meibomian glands. A monopolar tip is typically more uniform and rounded, allowing for more efficient heating and gland expression.
Radiofrequency safety considerations
Early RF units were designed and tested for aesthetic uses over broad areas of relatively thick skin. When one approaches the off-label use over thin, delicate eyelids with a relatively small surface area, the quality and responsiveness of the thermistor are critical.
The thermistor, located in the treatment handpiece, measures resistance to determine the temperature generated by the device in the skin. Under-regulated RF application can lead to underheating, resulting in diminished therapeutic effects. Alternatively, it can also cause overheating, which can lead to significant skin and eyelid burns.
In addition, when monopolar RF is used off-label to apply treatment “on lid” without the use of a protective shield, there is an added risk of concomitantly heating the cornea. In fact, in the technique of conductive keratoplasty (used for hyperopic refractive correction), RF was employed to alter the corneal curvature using compact, focal burns.
A note about eye shields
Plastic shields, like those in the thermaShield, are non-conductive to RF and offer full protection. However, using an RF handpiece without an eye shield to express meibum will result in retropulsion of the eye into the orbit, limiting the actual expression pressure.
With higher levels of pressure, there is a risk of significantly deforming the globe. To remedy this and enable optimal expression, thermaShield was designed with a flexible handle, allowing the lid to be fully supported at the level of the cornea.
The benefits of IPL for MGD
In addition to facilitating egress for stagnant meibum, meibomian glands can benefit from biological stimulation using a non-laser, high-intensity light source. Intense pulsed light uses a xenon flash lamp to produce a light output of wavelengths in the range of 400 to 1200nm.6
Unlike RF, IPL has been shown to have biomodulatory benefits that appear to be a “wake-up call,” stimulating the cells responsible for making tear components, including the meibomian gland oils. This clinically appears to help in rejuvenating meibomian gland form and function, and may even be synergistic with RF-heated expressions—and when required, meibomian gland probing—in bringing meibomian glands “back online.”7,8
Another benefit of light energy over radio energy (i.e., RF) is the capacity to help regress dilated, superficial blood vessels that facilitate the delivery of inflammatory cells and proteins into the eyelids and their respective glands. IPL has been shown to reduce the measurable cytokine levels in tissues, reducing inflammation.
Precise, intense broad-spectrum light also has antimicrobial benefits and can help eradicate Demodex mites in their in-vitro state. By reducing the germ burden while simultaneously boosting the anti-inflammatory effects, IPL can help support tear production and act as an adjunct to—or as a potential replacement for—oral antibiotics in the treatment of MGD and ocular rosacea.7,8
My experience-led protocol for treating MGD
While every patient is unique, in cases of obstructive MGD and concurrent lid inflammation, my general protocol is to do IPL followed immediately by heated expression. If a patient’s only problem is waxy, obstructive MGD, then any approved heated expression can be helpful (e.g., LipiFlow, TearCare, or iLux), though my personal preference is RF-heated expression (e.g., OptiPLUS).
On the other hand, if there is any related inflammation or severe MGD, adding IPL (e.g., OptiLIGHT) can be of enormous benefit. IPL alone typically takes three to four treatment sessions before patients experience significant relief. RF expression at the outset of IPL treatment can help to “jump-start” the patient’s relief.
The rationale for this is as follows: blockages are generally of a wax-like nature, with a high melting point; though IPL may heat enough to melt those plugs, the lids can cool so quickly that the waxy oils congeal back to an even thicker “toothpaste-like” consistency that is difficult to express.
However, RF can reheat the lids to allow effective expression. I find this works best with the lid supported by a thermaShield, so the oil remains liquid throughout the massaging action of the RF handpiece over the surface of the lid.
Always utilize IPL prior to RF
IPL purposefully “injures” the abnormal blood vessels delivering inflammatory cells and proteins. Once the treatment session is over, healing and vessel regression (shrinking) begin. Utilizing RF prior to IPL dilates the vessels, encouraging them to carry more blood and creating a “radiator effect,” which makes it harder for IPL to impact and regress the widely dilated vasculature.
In addition, I believe it is better to wait 3 to 5 weeks between IPL treatments to allow more complete healing and regression of these vessels. Delivering additional, higher levels of heat during this 3- to 5-week window may induce dilation of those vessels that were on their way to regression, causing them to re-establish their inflammation-bearing flow.
Personal pearls for success with RF and IPL
Successfully treating MGD requires both the best protocols and the best technology. By combining OptiLIGHT IPL with OptiPLUS—the first-of-its-kind, dual-frequency RF technology—I can implement my preferred treatment in a safe and efficient manner.
By providing a wide range of easily accessed RF frequencies and integrated programs, I’ve found OptiPLUS makes it “cookbook simple” to treat multiple depths within the same treatment and handpiece.
I have found using the right frequency with the best thermistors and internal controls to be OptiPLUS’s strong suit. Having a large, intuitive, easy-to-see control panel with readily programmed treatments is another key point. Lumenis also provides the training and support needed to get the full benefits from their technology.
Final thoughts
Because not all obstructive MGD has waxy plugs as the primary source of obstruction, some meibomian glands will develop internal and external blockages from “fibrosis” (i.e., scar tissue) and keratin plugging (gritty granules akin to hair and fingernail materials)—meaning there are times that additional tools are needed to unclog them.
Steve Maskin, MD, has patented small probes for this purpose and work continues on methods to restore severely damaged meibomian glands. Since RF-melted oils require little pressure for expression, the likelihood of damaging scarred or severely strictured glands is mitigated (as compared to colder expressions).
According to a study led by Michael A. Lemp, MD, approximately 85% of dry eye patients have some degree of MGD.9 Considering the fact that obstructive MGD appears to be the dominant finding among MGD causes, and waxy blockages are the common cause of these obstructions, a good, heated expression should help the vast majority of dry eye sufferers.
Therefore, implementing IPL in conjunction with RF to break the cycle of MGD-induced dry eye inflammation should be a component of the dry eye specialist’s armamentarium for the majority of dry eye sufferers.
Disclaimer: This article is not meant to offer medical advice or off-label promotion, but rather provide a means to answer common questions posed by dry eye doctors relative to RF and IPL.
Financial Disclosure: Dr. Jaccoma is a part-owner of eyeThera, a company that provides dry eye information and sells a non-conductive eye shield used in his treatments.
