Intraductal Meibomian Gland Probing

Intraductal Meibomian gland probing is a treatment in use for over a decade for Meibomian gland dysfunction (MGD). It was developed by Dr. Steven L. Maskin, an ophthalmologist who focuses his practice on the diagnosis and treatment of Dry Eye Syndrome and MGD. Diagnostically, the procedure confirms that glands are patent (meaning the central duct of the gland is unobstructed). Probing also reveals the presence of the fibrotic tissue, or suggests another status of the glands, e.g., dilated or non-functioning glands.

As a therapy, probing releases fibrotic vascularized tissue that invades the glands choking them off. By releasing the invading tissue, probing establishes patency of the gland’s central duct. With patency established, the functionality of non-functioning or partially functioning glands is restored. Glands can again synthesize and secrete meibum. (Meibum is the oil produced by the glands that makes up the outer layer of tear film. Meibum lubricates the ocular surface, slows the evaporation of tear film, and contributes to refraction (how the eye focuses). Having good quality and good quantities of meibum in the tear film is essential to good eye health and eye comfort.

The in-office procedure is non-invasive, usually performed with only topical anesthetic. A nerve block is sometimes injected into the brow and cheek areas. This fully numbs the eyelids. The injections are comparable to the shots dentists give patients before a tooth is drilled.

Periductal Fibrosis

Research has shown that periductal fibrosis is commonly found in eye lids with MGD.

In one study “of nearly twelve thousand glands with MGD that were probed, nearly 67 percent of all glands and 80 percent of obstructed glands had evidence of these fibrotic bands within 1 millimeter below the orifice surface, while over 90 percent of glands had this tissue within 2 millimeters.” (See: Your Dry Eye Mystery Solved, Yale University Press, 2022.

For more information, see “Expressible Meibomian Glands Have Occult Fixed Obstructions: Findings from Meibomian Gland Probing to Restore Intraductal Integrity.”)

Periductal fibrosis can occur as a single band anywhere along the length of a gland’s duct, or as multiple bands. It may be found near the gland orifice at the lid margin, where it can be seen at the slit lamp or with confocal microscopy, or further along the duct where it is hidden within the tissue of the lid.

Inserting a probe into the gland is currently the only sure way to clear the mechanical obstruction that consists of the fibrotic tissue. Heating the lids, massaging the lids, IPL, steroid drops, scraping the tissue of the lid margin at the base of the lashes, and other treatments, will not dissolve or somehow eliminate the invading and harmful fibrotic tissue that can develop anywhere along the length of the gland.

Safety of Meibomian Gland Probing

Since making the treatment available to patients worldwide, Dr. Maskin has himself probed hundreds of thousands of glands with no adverse effects.

Thirteen independent studies from around the world, in addition to those conducted by Dr. Maskin, also showed that probing is safe with no patients in any study experiencing adverse effects from the procedure.

Sometimes a drop of blood is seen at the orifice after probing. Mistakenly, some rsearchers have interpreted this drop as an adverse effect. In fact, the drop indicates that the vascularized (containing blood vessels) fibrotic tissue was released. In other words, the drop is a sign of a beneficial treatment rather than a harmful adverse event.

When the tissue is released, a popping sound can be heard. This popping sound has also been misinterpreted as an adverse effect by some researchers. In fact, the sound is completely benign, indicating only that the invading fibrotic tissue was released. It’s as benign as the sound you hear when you chew your food or brush your teeth.

Efficacy: Relief when Standard Care Failed

The 13 studies from around the world all showed that probing was effective in treating MGD. In fact, Meibomian gland probing was the only effective treatment after standard care had already been administered to all of the patients. (Patients in the studies had not improved after receiving standard care such as lid hygiene, warm compresses, lid massage, topical therapeutics, and a variety of other standard treatments.) 10 of the 13 studies, those available in English, were comprehensively and objectively reviewed in detail in this study published in 2023 in the journal Clinical Ophthalmology.  Read about the Comprehensive Review of Meibomian Gland Probing.

A study by Dr. Maskin and Whitney Testa showed that after probing, as long as the orifice was still intact, atrophied glands can regenerate after probing. For patients suffering with the painful symtpoms of MGD, this is especially promising news.

To learn more about Meibomian gland dysfunction, why glands atrophy, and why probing ducts to release fibrotic tissue restores gland functionality, see Your Dry Eye Mystery Solved, Chapter 3: The Miebomian Gland, Chapter 4: Meibomian Gland Dysfunction Explored and Chapter 11: Intraductal Meibomian Gland Probing.

Read the 2023 article in the peer-reviewed journal Clinical Ophthalmology:

Review of Literature on Intraductal Meibomian Gland Probing with Insights from the Inventor and Developer: Fundamental Concepts and Misconceptions

Some patients only need to be probed once, whereas others require repeat probing. Repeat probing is usually not required for a year. You can think about your Meibomian glands the same way you think about your teeth. Even though you brush your teeth twice a day, you still have them professionally cleaned twice a year by a hygienist. Similarly, even though you wash your eyelids every day and possibly apply warm compresses to your eyelids, or administer other treatments, if you have chronic MGD, you should have your Meibomian glands professionally maintained once a year.

View images of Meibomian gland probing

View video of Meibomian gland probing

Learn about the Meibomian gland probing experience

Meibomian Gland Probing Procedure

Probing typically involves 8 steps:

1) Examination
The lid margins and glands are examined with and without trans-illumination to evaluate patency (opening) of orifice and status of the glands, specifically looking at gland proximal (near the opening) and distal (deeper in the gland) atrophy, length of glands, and signs of ductal dilation suggestive of proximal obstruction. Glands are palpated individually to check for gland tenderness, usually seen with inflammation and obstruction, with presumed elevated intraductal pressure.

2) Anesthetic
To anesthetize, first a bandage contact lens is placed over the cornea, then a drop of proparacaine 0.5% or tetracaine 0.5% solution is placed in the conjunctival sac. A generous amount of jojoba ophthalmic anesthetic ointment is applied on the lower lid margin using a sterile cotton tipped applicator. The patient closes their lids for 10-15 minutes. There will be some mild burning, which gradually dissipates over 30 seconds. After 15 minutes, the patient opens eyes, and another drop of the topical anesthetic solution is placed into the conjunctival sac. The bandage contact lens is removed and residual anesthetic ointment is rinsed off the ocular surface.

3) Initial probing to completely open the glands
Probing begins with the shortest and stiffest probe, the 1 mm length probe. After penetrating the orifice with the 1 or 2 mm probe, if lid tenderness persists, the 4 mm probe is then used to achieve complete patency of the intraductal space.

4) Releasing fibrotic tissue
At times resistance may be encountered. After checking to ensure the probe is co-linear to the gland, additional mild force is used to release the intraductal fibrotic tissue. (The fibrotic tissue is released when the “pop” noise is heard. Multiple “pops” sound like nails on a washboard, indicating more than one band of fibrotic tissue was released.)

5) Dilating glands
After probing the glands, a dilator probe is seated on the orifice and advanced into the distal duct, about 1mm. Dilation of the orifice and central duct prepares the glands for steroid injection and lavage.

6) Injecting steroid (lavage)
A steroid ointment may be injected into the central duct to reduce inflamation and washout the intraductal space.

7) Rinsing after the procedure
Each eye is rinsed copiously with saline to remove residual anesthetic, and cotton tipped applicators are used to remove anesthetic from lashes.

8) Gland expression
Mild gland expression, applied very gently with a rolling expressor that directs gland contents toward the orifice, may be administerd to the lids.

9) Rinsing and follow-up care
The eyes and lids are rinsed copiously with sterile 0.09% sterile saline solution. The lids may be blotted gently to remove residual anesthetic ointment. Patients can use artificial tears every 30 to 60 minutes, if needed, until bedtime to wash away debris that is secreted from the now opened glands.

All glands of all lids may be probed initially and during follow-up procedures. Occasionally only some glands may be probed. After initial probing if several glands remain blocked, indicated by symptoms of persistent pain or foreign body sensation in the area of the blocked glands, only these glands may need to be re-probed.


Adapted from Intraductal Meibomian Gland Probing to Restore Gland Functionality for Obstructive Meibomian Gland Dysfunction (MGD)
Maskin SL, Kantor K.
Retrieved October 27, 2015 from


Studies conducted around the world indicate that intraductal Meibomian gland probing safely provides rapid and lasting relief, and significantly improves symptoms of MGD. Below are links to some of the articles, including Dr. Maskin’s first 2010 journal article on Meibomian Gland probing where he discusses his initial findings. Much more is now known about how important and effective Meibomian gland probing is for the treatment of MGD.

Growth of Meibomian gland tissue after intraductal Meibomian gland probing in patients with obstructive Meibomian gland dysfunction
Maskin SL, Testa WR.
British Journal of Ophthalmology
June 28, 2017
View the full report
Effectiveness of intraductal Meibomian gland probing for obstructive Meibomian gland dysfunction
Sik Sarman Z, Cucen B, Yuksel N, Cengiz A, Caglar Y
2016 Mar 30. [Epub ahead of print]
View the full report
Efficacy of intraductal Meibomian gland probing on tear function in patients with obstructive Meibomian gland dysfunction
Ma X, Lu Y.
2016 Mar 9. [Epub ahead of print]
View the full report

Analysis of meibum before and after intraductal Meibomian gland probing in eyes with obstructive Meibomian gland dysfunction
Nakayama N, Kawashima M, Kaido M, Arita R, Tsubota K.
2015 Oct;34(10):1206-8. doi: 10.1097/ICO.0000000000000558.
View the full report

Intraductal Meibomian gland probing for the treatment of blepharitis
Fermon S, Zaga IH, Alvarez Melloni D.
Archivos de la Sociedad Española de Oftalmología
2015 Feb;90(2):76-80. doi: 10.1016/j.oftal.2014.04.014. Epub 2014 Jul 5.
View the full report

Clinical research on intraductal Meibomian gland probing in the treatment of patients with Meibomian gland dysfunction
Qin Dongju,Liu Hui,Xu Jianjiang
Chinese Journal of Optometry, Ophthalmology, and Visual Science
2014, Vol. 16. Issue (10): 615-621 DOI: 10.3760/cma.j.issn.1674-845X.2014.10.009
View the full report

Efficacy of physiotherapy and hygienic procedures in treatment of adults and children with chronic blepharitis and Dry Eye Syndrome
Prozornaia LP, Brzhevskiĭ VV.
Vestnik oftalmologii
2013 May-Jun;129(3):68-70, 72-3
View the full report

Intraductal Meibomian gland probing in the management of ocular rosacea
Wladis EJ.
Ophthalmic Plastic and Reconstructive Surgery
2012 Nov-Dec;28(6):416-8. doi: 10.1097/IOP.0b013e3182627ebc
View the full report

Intraductal Meibomian gland probing relieves symptoms of obstructive Meibomian gland dysfunction
Maskin SL.
2010 Oct;29(10):1145-52. doi: 10.1097/ICO.0b013e3181d836f3
View the full report

Clinical Trials

Three clinical trials, one in the US and two in China, results available in English, were conducted on Meibomian gland probing. See the 2023 Clinical Ophthalmology review article for a detailed report and analysis of their results.