October 2017

CORNEA

Meibomian gland probing: The who, what, where, when, and why


by Liz Hillman EyeWorld Staff Writer


Meibomian gland intraductal probing of the upper lid to relieve fixed and non-fixed obstructions
Source: Steven Maskin, MD


Watch Dr. Maskin
perform meibomian gland probing on several patients.


Watch a patient’s testimonial of this procedure.


See Dr. Maskin release trapped meibum with meibomian gland probing.



Complete distal obstruction (left), as indicated by the orange band around the meibomian gland illustration, and complete proximal obstruction (right) show two different types of gland atrophy that could result from an obstruction and subsequent meibum buildup and pressure.
Source: British Journal of Ophthalmology/Steven Maskin, MD

The scoop on the technique that aims to relieve obstructive meibomian glands

Steven Maskin, MD, Dry Eye and Cornea Treatment Center, Tampa, Florida, first introduced the idea of inserting a wire probe into meibomian glands to relieve obstructions that could be causing discomfort and dry eye in 2010.1 Since then research has shown it to be, what he called, a “paradigm shift” in successful treatment of obstructive meibomian gland disease.2–4
Dr. Maskin gave EyeWorld an in-depth look at his tips and tricks on meibomian gland probing (MGP).

EyeWorld: What is MGP?
Dr. Maskin: Meibomian gland probing is the introduction of a wire instrument to the gland orifice with insertion through the orifice and into the ductal outflow tract.

EyeWorld: What’s the purpose of probing?
Dr. Maskin: Probing establishes and confirms with positive physical proof a patent outflow channel including duct and orifice. Probing, by relief of intraductal obstruction, is therefore able to equilibrate intraductal pressures within the duct and promote removal of sequestered and other retained intraductal contents. At times, the introduction of intraductal lavage or microtube injection of pharmaceutical will act to remove material that was not released with probing and subsequent expression alone. In summary, initial and maintenance probing: (1) relieves obstruction, (2) maintains patency of outflow channel, and (3) is associated with growth of meibomian gland tissue.

EyeWorld: What are the indications?
Dr. Maskin: Probing has become a first-line treatment for MGD in my practice to eliminate intraductal resistance to meibum flow from all types of obstruction. This includes fixed, unyielding obstruction such as periductal fibroses as well as non-fixed obstruction such as thickened meibum and hyperkeratinization. I also use it for gland maintenance to help prevent initial or progressive atrophy similar to a dental analogy of periodic prophylactic tooth scaling and cleaning. Now that we have seen and published on growth of gland tissue after probing, we are also exploring the use of probing with adjunctive injection therapies to further stimulate gland growth and restoration of a full, functional, healthy, and resilient meibomian gland lid population.5
I use probing on patients with lid tenderness over the meibomian glands (indicating elevated intraductal pressure). Probing dramatically and immediately relieves lid tenderness from elevated intraductal pressures. I use probing to restore functionality to non-meibum expressing glands, as well as to relieve symptoms of lipid tear deficiency. I also use probing to stimulate growth of gland tissue from glands with dropout or atrophy on meibography.

EyeWorld: Can you describe the probes used for MGP?
Dr. Maskin: The stainless steel probes are 76 µm in diameter with lengths of 1, 2, 4, and 6 mm. The probes are non-sharp to minimize alteration of tissue and allow the physician to better feel the tissue and resistance during the probing procedure rather than sharp blades that would slice their way through the tissue without yielding diagnostic information about the type and extent of resistance as well as likely cut through the duct wall, creating a false passage. Stainless steel is important to give the probe a stiffness to allow safe and quick penetration through the orifice and into the duct.

EyeWorld: How do you anesthetize a patient for this procedure?
Dr. Maskin: I use my patented jojoba-based anesthetic ointment (JAO) containing 8% lidocaine available from O’Brien Pharmacy (Mission, Kansas). After placing one drop of topical anesthetic into the inferior fornix, I place a bandage contact lens on the eye and a generous amount of JAO on the lower lid margins. The eye is closed for 10–15 minutes during which time both upper and lower lid margins are anesthetized. The eye is opened and a second drop of topical anesthetic is placed in the inferior fornix. If the patient’s lids are still sensitive after probing has begun, a second round of JOA applied to the lid margin is typically successful in making the procedure well tolerated. After probing is completed, the contact lens is removed and the ocular surface is copiously irrigated with sterile preservative-free saline. Then a cotton-tipped applicator is used to remove any residual JAO from eyelashes.

EyeWorld: Are there different approaches to anesthesia?
Dr. Maskin: An alternative approach uses topical proparacaine on the ocular surface followed by a corneal protective shell and a cotton pledget soaked in 4% lidocaine placed into the fornix for 5 minutes. Then 1% lidocaine with epinephrine is injected using a transconjunctival approach into the fornix centrally, medially, and laterally with supplemental subcutaneous injection near the eyelid margin.4

EyeWorld: How is the patient positioned during the procedure?
Dr. Maskin: While anesthetic is applied in a reclined position for MGP, I position the patient at the slit lamp for virtually all my probing. An assistant is there to support the back of the head, if necessary. Other physicians may prefer reclining a patient on a surgical chair and using an operating microscope.

EyeWorld: MGP can involve different probe lengths; how is probe length selected?
Dr. Maskin: I always begin with the 1-mm probe. The 1-mm probe is the shortest and stiffest and therefore most likely to penetrate through orifice or distal duct fibrosis or other unyielding fixed obstruction.
Longer probes are used if there is persistent lid tenderness over a gland suggesting deeper obstruction with elevated intraductal pressure. Longer probes can also be used to reach into a developing hordeolum to promote drainage. When using longer probes, always use progressively longer increments. After the 1-mm, use 2-mm, and then 4-mm probes, if necessary.

EyeWorld: How do you decide which glands are probed?
Dr. Maskin: I probe all orifices. This is important as I have seen glands with minimal associated acini restored to functionality after probing and start expressing meibum. Furthermore, now that we know there can be post-probing growth of meibomian gland tissue from previously atrophic glands, it is important to stimulate growth associated with all orifices and/or glands.5

EyeWorld: What techniques do you use to identify the gland orifice and insert the probe?
Dr. Maskin: It is usually not difficult to identify orifices. Some physicians use red-free light to assist. Transillumination or meibography can reveal location of glands as well.
Rest the tip of the 1-mm probe on the orifice. Using a dart-throwing motion, try to insert the probe into and through the orifice. This is done by holding the probe handle as you would hold a dart and using a short jab motion of 1–2 mm to penetrate through the orifice into the duct. The probe will enter the duct naturally and the duct itself will guide the probe, similar to your arm entering the sleeve of a shirt.
If you meet resistance, try a different entry angle for the dart-throw motion. The orifices and distal ducts may be dragged posteriorly or fibrosed in a way that requires an altered entry angle.

EyeWorld: Could the probe create a false passage?
Dr. Maskin: Probing does not create a false passage. When you penetrate the orifice and enter the gland, the effect is tantamount to passing your arm into your shirtsleeve. The probe simply follows the duct in the same fashion.

EyeWorld: What is the importance of probes being “non-sharp”?
Dr. Maskin: Probing is both a first-line treatment as well as a diagnostic test looking at the frequency and type of gland resistance, which may correlate with severity of symptoms. It is important when probing to do so effectively with minimal unnecessary disturbance of gland tissue. It should be noted that a post-probing confocal microscopy study has shown no degenerative changes in morphology of meibomian gland acinar units or meibomian gland scars.3

EyeWorld: What are the procedural findings of probing?
Dr. Maskin: When the probe is inserted through the orifice and into the central duct, you quickly encounter orifice and/or ductal resistance. This resistance may be relieved by advancing with the probe, generating an audible and tactile sensation of a “pop” or multiple pops causing an audible and tactile “gritty” sensation. The also patient hears and feels the pops and gritty sensation and can appreciate the instant relief of elevated intraductal pressure as the obstruction is relieved, intraductal pressures equilibrate, and meibum flow is restored with relief of tenderness.
Lid tenderness is dramatically and immediately relieved. Persistent lid tenderness suggests deeper obstruction requiring probing with a 2-mm or 4-mm probe.

EyeWorld: Is trapped meibum released?
Dr. Maskin: As the intraductal obstruction is relieved, you frequently see sequestered meibum release along the wire probe to exit through the now patent outflow channel and through the orifice.

EyeWorld: What about hemorrhages?
Dr. Maskin: Dot hemorrhages frequently appear at the orifice. These hemorrhages are self-limited and do not need pressure or any treatment.

EyeWorld: Is MGD something a tech could do?
Dr. Maskin: I can see the day when a trained physician assistant could do it.

EyeWorld: Is there any way to inject medication into glands after probing?
Dr. Maskin: Yes. With 110 and 152 µm tubes, we can deliver medication directly inside the gland, such as dexamethasone or small particle suspensions. Injections directly into the gland enable targeted treatment of gland dysfunction as well as removal of stagnant secretions with an irrigation or lavage approach. Early studies suggest we have found an adjunct microtube injection treatment to prolong onset of recurrent intraductal obstruction and reduce orifice hemorrhage upon retreatment probing. This would be meibomian gland orifice and duct reconstruction. We are also exploring the use of probing with adjunctive injection therapies to further stimulate gland growth and restore a full, functional, healthy, and resilient meibomian gland lid population.

EyeWorld: What should you be looking for on follow-up visits?
Dr. Maskin: It is important to remember that MGD with progressive gland atrophy can and will occur at a subclinical level without symptoms. Patients with symptoms relieved after probing who have become asymptomatic need to be monitored on every visit to detect early reobstruction with progression of disease even if the patient is symptom-free. This can include checking for lid tenderness and expressible glands on every exam plus meibography every few months. Symptom relief from MGP should last about 1 year. If symptoms reappear earlier or if there is a decrease in the number of expressible glands or increase in lid tenderness, there is an unrecognized or inadequately treated local, regional, or systemic comorbid disease. Probing provides positive physical proof of patency, but once achieved the patent outflow channel must be defended against all comorbid sources of inflammation that would reobstruct the outflow tract.

References

1. Maskin SL. Intraductal meibomian gland probing relieves symptoms of obstructive meibomian gland dysfunction. Cornea. 2010;29:1145–52.
2. Maskin SL. Intraductal meibomian gland probing: A paradigm shift for the successful treatment of obstructive meibomian gland dysfunction. In: Kazuo Tsubota, ed. Diagnosis and Treatment of Meibomian Gland Dysfunction. Tokyo, Japan: Kanehara;2016:149–167.
3. Dongju Q, et al. Clinical research on intraductal meibomian gland probing in the treatment of patients with meibomian gland dysfunction. Chin J Optom Ophthalmol. 2014;16:615–21.
4. Syed ZA, et al. Dynamic intraductal meibomian probing: A modified approach to the treatment of obstructive meibomian gland dysfunction. Ophthal Plast Reconstr Surg. 2017;33:307–309.
5. Maskin SL, et al. Growth of meibomian gland tissue after intraductal meibomian gland probing in patients with obstructive meibomian gland dysfunction. British J Ophthalmol. 2017 June 7. Epub ahead of print.

Editors’ note: Dr. Maskin owns patents on devices and methods of intraductal meibomian gland diagnosis, treatments, and topical therapies. He has financial interests with Rhein Medical (St. Petersburg, Florida).

Contact information

Maskin: drmaskin@tampabay.rr.com

Meibomian gland probing: The who, what, where, when, and why Meibomian gland probing: The who, what, where, when, and why
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