Eyeworld

EW CORNEA 28 January 2015 by Tony Realini, MD, MPH, EyeWorld Contributing Writer How effective is lid warming for meibomian gland dysfunction? M eibomian gland dysfunction (MGD) is a common finding among patients who seek eyecare. In many patients, the disease is complete- ly asymptomatic. In others, the severity can range from being a mild annoyance to significantly impact- ing vision and quality of life. "Meibomian gland dysfunc- tion 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 ocu- lar surface disease. "Timely interven- tion of MGD is important because progressive meibomian gland loss occurs with reduced quality and quantity of the meibum normally with age, without initial correspond- ing increases in dry eye symptoms," said Nisha Yeotikar, PhD, post-doc- toral 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 Phar- maceuticals, 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 devel- oped 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, random- ized 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 Schirmer's test <8 mm in 5 min- utes) and 75% had tear film insta- bility (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 symp- toms, he added, and the changes in the entire OAHFA lipid class inverse- ly 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 retrospec- tive 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 3–5 weeks after treat- ment, 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. F or many comprehensive ophthal- mologists 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 manage- ment 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 patient's tears evaporate too rapidly, which appears on slit lamp examination with fluo- rescein 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 tech- nologies 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 month's "Cornea editor's 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 Cornea editor's corner of the world Moderate meibomian gland dysfunction Source: Kelly K. Nichols, PhD

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