Eyeworld

EW CORNEA 112 October 2017 by Liz Hillman EyeWorld Staff Writer obstructed glands with MGP. As for the 59% of lids that did not show growth, the researchers wrote these patients still experienced relief from their symptoms. What's spurring gland growth? "One possibility to explain our find- ings is that the establishment of a patent orifice and duct permitted or perhaps promoted growth. This may be related to removal of the suppres- sive effect of elevated intraductal pressure on the proximal MG. Alter- natively, probing may activate MG stem cells with a direct mechanical intraductal stimulus," study authors wrote. As for why some probed glands grew but not others, one suggestion is surface inflammation and pro- gressive atrophy that occurs with aging and with other comorbidities that continue to affect glands post probing. Joseph Tauber, MD, Tauber Eye Center, Kansas City, Missouri, who started performing MGP in 2009 and has treated more than 1,200 unique patients in the time since then, said he thinks the phrase "growth" in this study is speculative, and "reca- nalization" might be a more appro- priate term. As for his experience with MGP, he began performing the procedure because he saw a clinical need for control of MGD symptoms and found current treatment regimens inadequate. "I began only with obstructive MGD but have more recently used it in highly symp- tomatic, less obstructed patients," Dr. Tauber said, anecdotally seeing 70–75% relief of patient symptoms. Dr. Maskin said a patient at any stage of MGD could benefit from probing. "Clearly, patients with lid tenderness, which suggests elevated intraductal pressure behind an ob- struction, would benefit, as well as patients with lids showing non-ex- pressible glands and eyes with lipid tear deficiency. Also, lids showing MG atrophy on infrared meibog- raphy or transillumination would benefit from MGP. Earlier detection of symptomatic MGD with grade 1 atrophy may allow for earlier inter- vention with relief of symptoms and reversal of atrophy. In asymptom- atic patients with atrophic changes, MGP may promote MG growth, thus preventing onset of symptoms or possibly reversing subclinical the obstruction, even if meibum is released from in front of the ob- struction, providing lubrication and some initial symptom relief. "This is why probing should be performed as first-line therapy to establish and/or confirm a patent outflow tract," Dr. Maskin said. "Probing relieves, unequivocally, all obstruction, non-fixed and fixed." His recent MGP research was a retrospective study that compared meibography results in patients with obstructive MGD pre- and post- MGP treatment. Thirty-four lids of 19 patients with pre- and post-MGP data were examined between 4.5 and 12 months post-MGP with 41% showing signs of gland growth, though four lids were excluded for meibographies with light artifacts, lid distortion, or hordeolum. Ten remaining lids from nine patients showed 116 glands total, which the study authors noted was a 4.87% in- crease in mean individual glandular area (MIGA). Four patients showed a MIGA increase of 10.7–21.1%. Be- tween 12 and 25 months post-MGP in nine additional patients, three lids were eligible for quantitative analysis with a total of 33 glands showing an increase in MIGA. "Collectively, for all 13 lids of the 149 glands studied, we found a significant increase of 6.38% in total glandular area (p=0.0447) and a sig- nificant increase of 6.23% in MIGA (p=0.0003)," Dr. Maskin said. Four types of gland growth were observed, including lengthening of shortened glands (which the study authors describe as reversal of prox- imal atrophy), partial restoration to faded glands, appearance of new glands, and restoration of a con- tinuous gland from discontinuous segments of MG tissue. "Successful MG growth is essen- tial to fully restore full, functional, healthy and resilient MG lid pop- ulations," the study authors wrote. "Healthy whole glands are preferable to functional yet partially atrophic glands. Whole glands can experience subsequent partial atrophy and still retain functionality, while already partially atrophic glands with ob- struction may lead to whole gland atrophy. There is clinical value to the resilience of a restored gland." The research also included several case-specific examples that showed gland growth after clearing raise intraductal pressure that can cause gland atrophy proximal to the obstruction. "We found approximately 75% of upper lid glands and 55% of lower lid glands have such fixed obstruc- tion," he said. Even if a gland is expressible, a deep obstruction could still lead to a short or truncated gland as the prox- imal tissue behind the obstruction undergoes atrophy, Dr. Maskin said. "This type of obstruction is fixed and unyielding and requires the intraductal passage of the probe to successfully relieve. The patient and physician both feel and hear the belt of scar tissue 'pop' off the duct as sequestered meibum is seen flowing out through the orifice along the wire probe," he said of the procedure. Recently, there have been newer MGD treatments coming to the market that heat and/or use pressure to relieve MGD and related dry eye symptoms, but Dr. Maskin said he thinks in the case of an unyielding, fixed obstruction, these techniques could exacerbate the problem in the long run. He explained that while these techniques might deliver meibum from a non-fixed obstruc- tion, using it in the case of a fixed obstruction could increase intraduct- al pressure, inflammation, and po- tentially cause increased symptoms and/or secondary atrophy behind Meibomian gland probing in obstructive MGD found to spur gland growth A study published in the British Journal of Ophthal- mology suggests that prob- ing meibomian glands in patients with meibomian gland disease (MGD) could lead to growth and regeneration of gland tissue. 1 Steven Maskin, MD, Dry Eye and Cornea Treatment Center, Tam- pa, Florida, first described meibo- mian gland probing (MGP)—using a sterile stainless steel wire (Maskin Meibomian Gland Intraductal Probe, Rhein Medical, St. Petersburg, Flori- da) passed into the gland to relieve obstructions—in 2010. 2 Since then, several studies have been published that suggest MGP improves symp- toms of obstructive MGD. 3–10 Dr. Maskin and coauthor Whitney Testa, Dry Eye and Cornea Treatment Center, described an increase in meibomian gland tissue area and growth of previously atro- phied glands after MGP. "Evidence suggests scar tissue wrapped as a tight sheath around the gland, squeezing the meibomian gland duct, [can create] a fixed, unyielding intraductal obstruction," Dr. Maskin said, going on to de- scribe how periductal fibrosis can Research finds meibomian gland growth after probing technique The rectangles in A, B, and C highlight the atrophic area where growth occurred. Pre-probing and post-probing image capture from IR meibography video (A) and after being processed through Adobe Photoshop to desaturate and invert the color image (B). (C) Shows traces of individual meibomian glands. Pre-probing images show proximal atrophy with shortened gland length while post-probing shows a lengthening of these glands. Source: British Journal of Ophthalmology

• Blank Page
• Blank Page (1)