Group efforts take dry eye diagnosis, treatment toward consensus
Dry eye has garnered increased attention in recent years, but experts still contend that the condition lacks an absolute definition.
It also lacks a universally accepted objective test. These factors complicate the diagnosis of the condition and, as a result, the management of patients with the disease, according to Paul M. Karpecki, OD, FAAO, of Koffler Vision Group and a Primary Care Optometry News Editorial Board member.
“We’ve never really had any ideal tests for dry eye,” Dr. Karpecki said in an interview. “Schirmer’s [test] is erratic and its sensitivity is extremely low, so we try to go off symptoms and then hope to find some signs that support it. However, the problem is that a lot of patients don’t have symptoms.”
In the absence of definitive clinical signs, it may be difficult to know when to initiate therapeutic management. Often, palliative relief is depended on, Dr. Karpecki said, but, in the long run, that may serve as a detriment to patients. Although few studies have correlated a lack of treatment with progression of disease, Dr. Karpecki is nonetheless convinced of the degenerative nature of dry eye syndrome.
“I am convinced that it progresses and does get worse,” he said. “I have seen patients who have been palliatively treated for an extensive period of time, and the disease only seems to advance.”
When initiated, however, therapy can be highly successful in helping patients manage their chronic condition, even if an absolute cure is not currently available.
“There is benefit to treating dry eye,” Dr. Karpecki told PCON. “But, truly, the longer the disease has been present, the more chance there is of ocular damage.”
Patient factors raise the index of suspicion
Despite the lack of objective testing and a clear definition, trademark patient-reported symptoms and hallmark clinical signs can be useful in making a diagnosis.
According to Dr. Karpecki, a patient questionnaire can be a useful screening protocol for deciding on whom to pursue further testing. Currently, the use of fluorescein and lissamine green or rose bengal staining are the gold standard for assessing the ocular surface, and tear film break-up time can give a good indication of the tear function.
However, Dr. Karpecki added, these tests are not always performed properly or in a consistent manner. Often, too little fluorescein is placed in the eye or too much of the stain is added, which saturates the eye and results in a variable and confounded response.
“Waiting exactly 1 minute after putting fluorescein in, knowing exactly how much lissamine green or fluorescein to put in each time, looking for consistent tear film break-up patterns as opposed to the very first – things like that can then eliminate some of the variability,” Dr. Karpecki said. However, “it takes practice to do them consistently.”
Patient-specific risk factors may also be a clue to diagnosis. Female gender and age have been associated with a risk for developing dry eye, and certain medical conditions – diabetes, arthritis, thyroid disease, rosacea – or medications taken to treat concomitant medical maladies – antihistamines, hormone replacement therapy, diuretics, anti-arrhythmia medications – may also contribute.
Epidemiologic studies have also identified environmental risk factors that suggest that while the incidence or prevalence of dry eye may not be changing, the absolute number of patients with either episodic or dry eye disease is on the rise. Major population-based studies to date have reported a wide variance in prevalence of dry eye, ranging from 5% to 30% or higher.
Dry eye workshop
That wide range may reflect the lack of definition and the lack of diagnostic criteria, according to Janine A. Clayton, MD, deputy director, Office of Research on Women’s Health, National Institutes of Health. Dr. Clayton chaired a subcommittee on the epidemiology of dry eye disease during the 2007 International Dry Eye Workshop (DEWS), which was an effort to consolidate the knowledge base on dry eye.
“Each of those studies had different definitions of dry eye and they had populations that were different ages in some cases,” Dr. Clayton told PCON in an interview. “It has been suggested that there is some variability, some real differences in the prevalence of dry eye, in various populations around the world, and that there are some ethnic and racial differences.”
What is certain, Dr. Clayton said, is that individuals are living longer and more active lives (the U.S. Census Bureau predicts a 100% rise in the number of individuals between 65 and 84 years old by 2050 and a 333% rise in those older than 85), and that the rise of video screen use and environmental pollutants challenge the ocular surface. This means that in all likelihood, dry eye will increase in prominence in the public health sphere.
In addition, epidemiologic studies on incidence and prevalence may not even account for all of the associated morbidity for patients with dry eye, which include the costs and burdens of patient management related to lost work time and impact on the health care system.
“There are more challenges to the ocular surface – be they environmental, chemical, occupational, recreational, computer use, aging – that will likely combine to increase the number of people who will be seeking dry eye treatment and who will be affected by dry eye,” Dr. Clayton said.
The lack of a clear definition and uniform diagnostic criteria have contributed to a lack of consensus on the ideal therapeutic option for treating dry eye, according to Terrence P. O’Brien, MD, a professor of ophthalmology at Bascom Palmer Eye Institute of the University of Miami School of Medicine. Dr. O’Brien participated in the Delphi Panel on dry eye and the Meibomian Gland Dysfunction Workshop, two international collaborative efforts in the past decade to attempt to build consensus on diagnosis and management of ocular surface disease.
“Visual function is impacted by dysfunctional tear states, and in the past the impact of dry eye is something that has been ignored,” Dr. O’Brien said in an interview. “If you do not treat, these conditions can become chronic and progressive, and symptoms and signs get worse over time. The progressive nature has to be taken into account in treatment and decision-making.”
The Delphi Panel identified four levels of dry eye, each one having its own treatment recommendations. The panel also recommended the use of symptoms and clinical signs on exam for the initial diagnosis, with testing serving a confirmatory role.
“We do not have any one single test that is absolutely pathognomonic or diagnostic,” Dr. O’Brien said. “In terms of the severity criteria we used in the Delphi Panel and the Dry Eye Workshop, the severity and frequency of dry eye symptoms is one thing, and visual symptoms and signs are another.”
Fundamentally, though, Dr. Karpecki said, suggestions for the ideal treatment of dry eye have reached a consensus, starting with environmental management – reducing exposure to windy condition, positioning a computer screen below eye level, refining prescription drug regimens when appropriate – and moving on to the use of disease-targeting medications for any patient with non-episodic dry eye.
According to Dr. Karpecki, treatment should be initiated as soon as possible to avoid degeneration, and for more advanced disease, corticosteroids, nutritional supplements and cyclosporine are beneficial.
“Even at the early stage, often palliative treatments are not sufficient to prevent the progression of the disease,” Dr. Karpecki said. “There is research showing the benefits of fish oil, which is EPA [eicosapentaenoic acid] and DHA [docosahexaenoic acid], and significant number of studies showing the benefit or GLA, gamma-linolenic acid, which is an omega-6.”
For more information:
- Paul M. Karpecki, OD, FAAO, is a member of the Primary Care Optometry News Editorial Board. He can be reached at Koffler Vision Group, Eagle Creek Medical Plaza, 120 N. Eagle Creek Drive, Suite 431, Lexington, KY 40509; (859) 263-4631; e-mail: email@example.com.
- Janine Austin Clayton, MD, is deputy director of the Office of Research on Women’s Health. She can be reached at the National Institutes of Health, Department of Health and Human Services, 6707 Democracy Blvd., Suite 400 MSC 5484, Bethesda, MD 20892-5484; (301) 402-1770; fax: (301) 402-1798; e-mail: Janine.Clayton@nih.gov.
- Terrence P. O’Brien, MD, can be reached at Bascom Palmer Eye Institute, 7108 Fairway Drive, Palm Beach Gardens, FL 33418; (561) 515-1544; fax: (561) 515-1588; e-mail: firstname.lastname@example.org.