The line of Marx (LOM) is the mucocutaneous junction that separates the anterior keratinized epithelium from the palpebral conjunctiva (Doughty, 2013). Under normal circumstances, the LOM resides posterior to the meibomian glands (MGs) on both the upper and lower lid margins (Korb and Blackie, 2010; Yamaguchi et al, 2006).
Literature review and practical experience have demonstrated that the LOM migrates anteriorly over time with chronic ocular surface disease (Yamaguchi et al, 2006). In the most severe cases, it will migrate anterior to the MG orifices (Yamaguchi et al, 2006). Interestingly, debriding the lower lid margin including the LOM with a metal golf spud can improve meibomian glands yielding secretions (MGYS) and dry eye symptoms in patients who have meibomian gland dysfunction (MGD) (Korb and Blackie, 2013).
The LOM is also a key anatomical structure to understand the lid wiper (LW) and lid wiper epitheliopathy (LWE). The LW is located posterior to the LOM on the upper lid and provides the “wiping action” of the lid along the ocular surface with blinks. In cases of ocular surface disease, there is excessive friction between the LW and the ocular surface. This compromises the integrity of the tissue (Efron et al, 2016), causing the staining that we know as LWE; it is correlated with both dry eye disease and lens discomfort (Korb et al, 2002; Korb et al, 2005). Practitioners should strive to be proactive in preventing these chronic, long-term changes to improve outcomes for patients.
Case in Point
A new 48-year-old female patient had noticed increasing discomfort with her daily disposable multifocal contact lenses and was taking them out much earlier than previously. Some days she didn’t even wear them because of the discomfort. Her vision also wasn’t as good when her lenses were less comfortable.
She was not taking any medications and had no known allergies. Her posterior segment evaluation was normal. The anterior segment evaluation at the slit lamp appeared normal. The patient’s MGYS were seven on each of the four lid margins. This demonstrates significant MG obstruction and a significant reduction in MG functionality. When viewed with the lissamine green, the LOM was slightly irregular on all four lid margins, more notably on the lower lids. LWE was noted on both upper lids.
We explained to the patient that MGD was causing her contact lens discomfort. We started her on an ocular nutritional supplement that had high levels of omega-3s, and we performed an advanced MG warming and evacuation procedure. Our goal was to improve MG functionality while mitigating any further irregularity in the LOM and LWE.
Two months later, all signs of LWE were absent. The MGYS were 12 on each of the four lids, which was a significant improvement. Most importantly, both comfort and vision improved, and we have re-normalized the way that the lids function with the ocular surface.
The Verdict
Today, we can intervene in ways that we never could in the past to help prevent the chronic changes of ocular surface disease. This means preventing the anterior migration of the LOM and the symptomatic sequela associated with these changes. If the meibomian glands crossing the LOM is normal, we don’t want to be normal. CLS
READ MORE: https://www.clspectrum.com/issues/2020/july-2020/is-this-the-new-norm
