EyeWorld Asia-Pacific December 2015 Issue

51 EWAP CORNEA December 2015 Views from Asia-Pacific Kazuo TSUBOTA, MD Department of Ophthalmology Keio University School of Medicine 35 Shinanomachi, Shinjuku-ku, Tokyo, Japan Tel. no. +81-3-5363-3269 Fax no. +81-3-3358-5961 Tsubota@z3.keio.jp R ecently, dry eye is considered to be a tear-film and pain disorder. The tear film consists of three layers: lipid, aqueous, and mucin. If any one of the three layers is not functioning properly, initially, the other two layers will compensate for the dysfunctional layer, but eventually becoming totally dysfunctional. This is known as an unstable tear film. In Japan and other countries in East Asia, this condition is commonly called short break-up time (BUT) type of dry eye. In addition, pain is a problem of neuropathology of the cornea or a very sensitive neuralgic condition. So now we can approach the dry eye patient through stabilizing the tear film layer or targeting the sensory part. Inflammation is very important for sensitizing the sensory receptors so if we can suppress inflammation, the patient’s symptoms can be alleviated. Recently, dry eye patients not only experience heavy sensation or ocular fatigue, but their visual function is also affected. And visual function is affected by the unstable tear film. With unstable tear film, higher-order aberrations increase and visual acuity over time, known as functional visual acuity, deteriorates. Thus, I believe we should focus on the stabilizing the tear film and alleviating abnormally activated pain receptors. Editors’ note: Dr. Tsubota has a patent pending for a visual acuity measurement system. what component of this could be neuropathic pain. I don’t think we do a great job of diagnosing or treating it,” she said. The pain that these patients experience may be associated with pain syndromes such as fibromyalgia or depression. However, even in those cases, the actual cause of pain can be murky. For example, she said, is the depressed patient with ocular pain over-interpreting normal sensations, does he or she have a charged-up nervous system causing more pain, or is he or she taking medications with ocular side effects such as drying? Dr. Hammersmith would consult with a patient’s primary care physician when appropriate to prescribe medications like pregabalin to address pain. Sometimes the medication helps— sometimes it doesn’t. She has also seen some success with the use of the BostonSight PROSE (prosthetic replacement of the ocular surface ecosystem) lens, which creates a moisture chamber around the eye. Experimental therapies for dry eye Ophthalmologists in the U.S. currently have only one pharmacologic agent approved for dry eye, said Deborah S. Jacobs, MD , medical director, Boston Foundation for Sight, Needham, Mass. That makes clinicians eager for new dry eye therapies, she said. “We’d all like to find one drug that would work for all of these patients. Unfortunately, the experience in the last 10 to 20 years [has demonstrated that] it’s hard to show effectiveness across broad populations. So, we have agents available that might work for some but not all patients,” she said. Some chronic graft-versus-host disease patients have responded favorably to topical anakinra, a human interleukin-1 receptor antagonist related to the drug EBI- 005 (Eleven Biopharmaceuticals, Cambridge, Mass.), the latter of which is in trials for dry eye disease and allergic conjunctivitis. Dr. Jacobs would also like to learn more about lifitegrast (Shire, Lexington, Mass.), another drug undergoing trials for dry eye treatment. “Regardless of the approved indication, any new drug such as lifitegrast or EBI-005 is likely to be useful in a subset of patients,” she said. Colleagues in Japan have described their effective use of rebipamide for some types of OSD. Rebipamide is a secretagogue approved and available there, Dr. Jacobs added. “The barriers to U.S. approval seem to preclude introduction of that drug or other secretagogues here [in the U.S.],” Dr. Jacobs said. “It is disappointing in the current environment; the quest for broad indications means that patients with moderate to severe disease related to specific etiologies don’t have access to drugs from which they might benefit,” she said. Blepharokeratoconjunctivitis in children Blepharitis in the pediatric population tends to be under- recognized and frequently misdiagnosed as allergic conjunctivitis or chronic conjunctivitis by the child’s primary care provider, said Jose de La Cruz, MD , assistant professor of ophthalmology, cornea service, Illinois Eye and Ear Infirmary, Chicago. “Only after a more thorough slit lamp examination can the findings of lid inflammation, meibomian gland inspissation, and/or findings of lid rosacea be discovered,” he said. Causes of blepharokerato- conjunctivitis in children include bacteria such as Staphylococcus , acne rosacea, or scalp dandruff. Aggressive lid hygiene with baby shampoo is the first line of defense to counteract the inflammatory response, Dr. de la Cruz said. “In the pediatric population, the expectation that the child will use a warm compress daily for at least 20 minutes is perhaps unrealistic,” he said. Because of this, medications to help with acute irritation and discomfort are often used. This includes a short burst of low concentration corticosteroid in an ointment or drop applied directly to the lid margin. Another helpful agent is an azithromycin ophthalmic drop directly applied to the lid margin twice a day for 7 to 10 days. “The combination of both provides a fast track to stabilizing the irritation to the ocular surface,” Dr. de la Cruz said. It is also important for physicians to treat seborrheic blepharitis and acne rosacea, Dr. de la Cruz said. However, he advises great care with the use of systemic medications such as doxycycline in children and recommends consulting the child’s pediatrician or dermatologist to assess any associated long-term risks. Limbal stem cell deficiency Chemical injuries and severe immunologic disease such as Stevens–Johnson syndrome are some of the most common causes of LSCD as seen by Ali Djalilian, MD , associate professor of ophthalmology, cornea service, and director, Corneal Epithelial continued on page 52