Meibomian glands are the oil glands along the edge of the eyelid that secrete a fluid known as meibum to prevent tear evaporation and protects the eye surface. As a person ages, the meibomian glands shrink, known as meibomian gland dysfunction, and this leads to evaporative dry eye disease. This causes swollen eyelids, itchy eyes, or blurred vision. There are treatments and research is being done on this condition.
Treatments Beyond Over the Counter Medicines and Home Remedies
While warm compresses and artificial tears temporarily relief symptoms, there are other treatment that are more effective in managing the condition. One such treatment is intense pulsed light (IPL). This uses a flash lamp to create a spectrum of polychromatic light ranging from 500nm to 1200nm, which is filtered to deliver specific photothermal effects on select tissue. This procedure targets the abnormal blood vessels that lead to the inflammation around the eyelids and is successful in both reducing the number of abnormal blood vessels and inflammation, as well as improving tear film quality.
A newer treatment involves neurostimulation of the nasolacrimal reflex. This involves stimulation of the nerves that control the tear flow from the eyes into the nose. There are two neurostimulation options available to treat meibomian gland dysfunction. One is Varenicline, a nasal spray that stimulates the nicotinic acetylcholine receptors in the nasal mucosa. It activates the trigeminal parasympathetic pathway, which is the nerve pathway that controls certain involuntary functions, like tear production and saliva secretion. Regular use of Varenicline increases tear production. Of course, patients need to learn how to use this nasal spray, in order to reduce unwanted side effects, such as excessive sneezing.
The other treatment that utilizes neurostimulation of the nasolacrimal reflex is a handheld device called iTear100. This device contacts the skin where the nasal cartilage meets the nasal bone. The patient turns it on and the tip vibrates for 30 seconds at a frequency of 220Hz to 270Hz and an amplitude of 0.5mm to 1mm. This stimulates the meibomian gland and improves secretion.
There are also pharmaceutical options for patients to consider. In 2023, Bausch + Lomb introduced Meibo, the first prescription drug to treat tear evaporation caused by meibomian gland dysfunction. This is 100 percent perfluorohexyloctane. There is no water, preservative or other inactive ingredient in this medicine. The perfluorohexyloctane is a chemically inactive substance with the ability to attach to both air and lipid molecules. This allows Meibo to form a layer on top of the tear film that makes a stable, anti-evaporative layer that can last up to six hours. This layer stabilizes the tear film, reduces friction, helps ocular surface healing by mimicking natural meibum, and prevent excessive tear evaporation.
Meibomian Gland Dysfunction & Stem Cells
As with most medical conditions, research is taking place to learn more about meibomian gland dysfunction and to develop other treatments for the condition. A team from the Icahn School of Medicine at Mount Sinai in New York City, discovered stem cell populations and mechanisms that lead to meibomian gland dysfunction. As a person ages, the meibomian glands may shrink, partly due to stem cell exhaustion.
Scientists used a mouse model in their work since the meibomian glands of mice have a similar structure to those of humans. They did single nuclear RNA sequencing linage tracing in a living organism, in this case, mice. Researchers also did live imaging, and genetic gain- and loss-of-function studies. In addition, they studied the gene expression in samples from normal human eyelid and samples from human meibomian gland carcinoma samples, a rare and aggressive cancer of the eyelid.
They were able to find markers for stem cell population that maintain specific regions of the meibomian gland. Scientists also discovered that the hedgehog (Hh) cell signaling pathway, which plays an important role in cell proliferation and differentiation, tissue development and homeostasis, is a regulator of meibomian gland stem cell proliferation and tissue regeneration. It was found that increased Hh signaling is a characteristic of human meibomian gland carcinoma.
In addition, scientists found that aged glands showed lower Hh cell signaling, less epidermal growth factor receptor (EGFR) signaling, impairment in nerves supplying tissue with nerve fibers, known as innervation, as well as a loss of collagen in niche fibroblasts. These things suggest that changes in the glandular epithelial cells and their surrounding environment contribute to age-related degeneration of the meibomian gland. These discoveries imply that targeting Hh and the EGFR signaling to stimulate stem cell activity in the meibomian gland could be a treatment option for meibomian gland dysfunction.
A person with meibomian gland dysfunction isn’t just stuck with using home remedies or over the counter medicines to manage the symptoms. There are advanced treatments for this condition. Also, thanks to medical research, more is being learned about meibomian gland dysfunction. So, getting older doesn’t have to be a drag—at least when it comes to vision.
Sources:
https://www.reviewofoptometry.com/article/expanding-the-mgd-treatment-arsenal