January 2015

 

CORNEA

 

Cornea editors corner of the world

How effective is lid warming for meibomian gland dysfunction?


by Tony Realini, MD, MPH, EyeWorld Contributing Writer

 
 

Clara Chan, MD

For many comprehensive ophthalmologists and even those who are primarily involved in subspecialty tertiary ophthalmic care, at times it feels as if there is a dry eye and blepharitis pandemic. Improved understanding of meibomian gland dysfunction (MGD), its pathophysiology, and its role in causing dry eye symptoms has led to more management options for patients. In MGD, abnormal meibomian glands that are blocked by thickened meibum secretions or atrophied in advanced cases lead to a deficient lipid layer of the tear film. When this occurs, the patients tears evaporate too rapidly, which appears on slit lamp examination with fluorescein and cobalt blue light as a decreased tear break-up time. A mainstay of treatment for MGD is warm compresses in order to soften the meibum such that it may flow out of the meibomian glands better. New technologies have emerged to mechanize this process for patients and to standardize the methods by which warm compresses and massage of the lid margins are performed. In this months Cornea editors corner of the world, Veronica Canton, MD, Louis Tong, PhD, and Nisha Yeotikar, PhD, discuss the details of their studies on the effects of lid warming and changes in various components of lipids expressed from the meibomian glands after treatment.

Clara C. Chan, MD, FRCSC, FACS, cornea editor

 
Meibomian gland dysfunction

Moderate meibomian gland dysfunction Source: Kelly K. Nichols, PhD

Meibomian gland dysfunction (MGD) is a common finding among patients who seek eyecare. In many patients, the disease is completely asymptomatic. In others, the severity can range from being a mild annoyance to significantly impacting vision and quality of life.

Meibomian gland dysfunction is defined as a chronic, diffuse abnormality of the meibomian glands, commonly characterized by terminal duct obstruction and/or qualitative/quantitative changes in the glandular secretion, as per the International Workshop on MGD by the Tear Film and Ocular Surface (TFOS) Society. This may result in alteration of the tear film, symptoms of eye irritation, clinically apparent inflammation, and ocular surface disease. MGD is thought to be among the most common causes of dry eye syndrome. In MGD, the lipid layer of the tear film is deficient, allowing evaporation of the aqueous layer, which leads to subsequent dryness and the signs and symptoms of ocular surface disease. Timely intervention of MGD is important because progressive meibomian gland loss occurs with reduced quality and quantity of the meibum normally with age, without initial corresponding increases in dry eye symptoms, said Nisha Yeotikar, PhD, post-doctoral research fellow, Brien Holden Vision Institute, Sydney, Australia.

Treatment for symptomatic MGD can range from lid scrubs to remove lid margin debris and clear the ducts, to lid warming to soften meibum and facilitate its egress from the ducts, to systemic therapy with tetracycline drugs, which are antibiotics but have the benefit of also softening meibum to aid its expression from the ducts. Products include the Korb MGE (meibomian gland evaluator), LipiView II, and LipiFlow (TearScience, Morrisville, N.C.); MG Expressor Kit (Gulden Ophthalmics, Elkins Park, Pa.); MiBoFlo ThermoFlo (Pain Point Medical Systems, Dallas); and Maskin Meibomian Gland Intraductal Probe (Rhein Medical, St. Petersburg, Fla.). Drugs involved include cyclosporine agents such as Restasis (Allergan, Irvine, Calif.), as well as AzaSite (1% azithromycin ophthalmic solution, Akorn Pharmaceuticals, Lake Forest, Ill.), which has shown potential in reports.

Lid warming can be achieved in a number of ways. Simply standing under a hot shower may be effective in mild disease. Warm compresses can be useful as well. In addition, several products have been developed to standardize and semi- automate the lid warming process.

The case for lid warming

Just how effective is lid warming in patients with MGD? To address this issue, Louis Tong, DM, PhD, and colleagues at the Singapore National Eye Centre conducted a prospective, randomized trial evaluating various methods of lid warming and their effect on lipid levels in meibum. Subjects with MGD were enrolled; approximately half had aqueous deficiency (defined as Schirmers test <8 mm in 5 minutes) and 75% had tear film instability (defined as tear film break-up time <3 seconds).

Methods of lid warming in this study included the standard hot towel compress as well as 2 commercially available systems, EyeGiene (Eyedetec Medical, Danville, Calif.) and Blephasteam (Thea, Clermont-Ferrand, France). Tear lipids were collected and analyzed at baseline and 12 weeks after treatment, and infrared meibography was utilized to assess meibomian gland dropout and thermography utilized to measure tear evaporation rates.

Treatment-induced change was observed for 30 distinct lipids, Dr. Tong said. Of these, 7 increased in concentration with treatment and 23 decreased in concentration. Most of the lipids that increased were O-acyl omega hydroxy fatty acids (OAHFAs), which are the lipids deficient in dry eye. Two of the 30 lipids with significant changes after treatment, both OAHFAs, correlated with improvements in dry eye symptoms, he added, and the changes in the entire OAHFA lipid class inversely correlated with changes in the evaporative rate. As these lipid levels rose, the tear lipid layer gained integrity and evaporation slowed.

Are warm compresses adequate?

Veronica Canton, MD, and colleagues at the University of Milan, Italy, conducted a retrospective study to compare the efficacy of warm compress heat therapy to a commercial wet chamber warming goggle device in treating mild to moderate MGD. All patients completed the Ocular Surface Disease Index (OSDI), a validated self-assessment of ocular surface symptoms, before and after therapy. In addition, Dr. Canton compared in vivo scanning confocal microscopy of meibomian glands before and 35 weeks after treatment, assessing various parameters including the density and diameter of acinar units and the diameter of the duct orifices. These parameters were graded from images read by investigators masked to treatment, she said.

Before treatment, the groups were similar in age and gender as well as clinical and microscopy status, she said. This is important in a retrospective study in which patients may have been treated differently based on differences in presentation, which can introduce bias.

Overall, both treatments were effective. Both groups showed significant improvements in OSDI scores, increased tear break-up time, and improvements in gland morphology by microscopy, she said. The only between-treatment difference was a greater decrease in meibomian gland diameter in the goggles group compared to the hot towel group. Also, based on the previously validated OSDI Minimal Clinically Important Difference, we found 4 subjects in the hot towel group and only 1 in the goggles group that showed no improvement in OSDI scores.

Practical implications

These data support the role of lid warming for symptomatic MGD.

The lipids deficient in dry eye, such as OAHFAs, are increased by lid warming treatment, concluded Dr. Tong. The change in 2 lipids correlates to the extent of symptomatic improvement. Also, lipid changes correlate to the change in tear evaporation, suggesting a functional role of lipids in MGD. Dr. Canton agreed. Eyelid warming is the mainstay of the treatment of mild to moderate MGD. While there were few differences between the hot towel and goggles groups in her study, she did point out that there might be value in using devices that are able to increase standardization and compliance to therapy.

References

Canton V, Garoli E, Villani E, et al. Comparative analysis of clinical and confocal outcomes in patients with meibomian gland dysfunction treated with warm compresses versus wet chamber warming goggles: a retrospective study. ARVO 2014 annual meeting abstract.

Sim HS, Petznick A, Tong L, et al. A Randomized, Controlled Treatment Trial of Eyelid- Warming Therapies in Meibomian Gland Dysfunction. Ophthalmol Ther. 2014 Aug 26. [Epub ahead of print]

Yeotikar NS, Zhu H, Omali NB, et al. The natural history of meibomian glands: Age-related changes in an asymptomatic population. Invest Ophthalmol Vis Sci 2014;55: E-Abstract 21, ARVO 2014 annual meeting abstract.

Editors note: Drs. Canton, Tong, and Yeotikar have no financial interests related to their comments.

Contact information

Canton
: veronica.canton@libero.it
Tong: Louis.tong.h.t@snec.com.sg
Yeotikar: n.yeotikar@brienholdenvision.org

How effective is lid warming for MGD? How effective is lid warming for MGD?
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