DRY EYE DISEASE
Make Dry Eye a Priority
Two reasons dry eye disease should command the same diagnostic attention as glaucoma.
WILLIAM TOWNSEND, O.D., CANYON, TEXAS
ILLUSTRATION BY SHARON & JOEL HARRIS
Although the onset of both dry eye disease (DED) and glaucoma can go unnoticed by patients, are chronic, increase in prevalence with age and have a significant impact on patients’ vision and quality of life, most ECPs put glaucoma far above DED on their diagnostic radars. While DED does not cause blindness in most cases, it should be given the same attention as the silent thief of sight.
Here, I explain why.
1 It’s more prevalent.
The prevalence of primary open angle glaucoma (POAG) varies among ethnic groups and is strongly influenced by age. The rates in white populations range from 1.5% in those age 50 to 54 to 8% in those 80 and older, according to recent NEI research. The rates in black populations range from 2% in those age 50 to 54 to 12% in those 80 and older. Meanwhile, the rates of the disease in Hispanics is 1.5% in those age 50 to 54 and 10% in those age 80 and older. A total of 14.4% of the U.S. population older than age 50 has DED, says a study in Investigative Ophthalmology & Visual Science. Numerous studies confirm age-related changes in tears and the ocular surface as decreased tear secretion rate and reduced tear volume, accompanied by declining concentration of tear proteins (i.e. lysozyme and lactoferrin).
In addition, meibomian gland dropout is associated with the effects of aging on meibomian gland secretions and anatomy, research reveals.
The percentage of individuals age 65 and older will more than double between 1950 and 2050, according to the Federal publication, “The Changing Demographic Profile of the United States.”
DED is associated with a number of variables, including the environment (patient proximity to air conditioning and heating vents, outdoor pollution, computer use, etc.), and a U.S. epidemic of unhealthy diet (high intake of salt, fats, alcohol, caffeine, etc.). Other contributory factors include extensive use of anticholinergic medications (antihistamines, decongestants, tricyclic antidepressants, etc.), contact lens wear (36 million Americans wear contact lenses) and autoimmune diseases (rheumatoid arthritis, systemic lupus erythematosus, HIV, Sjögren’s syndrome, acne rosacea, Stevens-Johnson syndrome, diabetes and thyroid disease). These, plus a myriad of other factors, such as hormonal changes and refractive surgery, have contributed to our current DED epidemic.
Systemic diseases contribute to the increasing prevalence of DED. Diabetes, for example, affects a total of 8.3% of the U.S. population. The American Diabetes Association reports that Type 2 diabetes is far more common than Type 1 diabetes, which comprises 5% of cases. Diabetes is linked to increased tear film osmolarity and a higher incidence of DED, research shows. In addition, tear proteins in diabetics are altered from normal profiles, research reveals.
Thyroid diseases affect roughly 4.6% of the U.S. population age 12 and older, reports the National Endocrine and Metabolic Diseases Information Service. One in eight females suffer from some form of thyroid disease. The odds ratio for DED in individuals with hypothyroidism is almost twice that of healthy individuals, research shows.
2 It has spawned new tech and treatments.
In the past decade, DED diagnostic technology and treatment has evolved tremendously, enabling us to be more effective in both areas. This, in turn, has increased the likelihood of patient satisfaction, which leads to patient loyalty and referrals. These advances:
▸ LipiView (TearScience). This device, which came to market in 2009, facilitates the evaluation of lipid layer thickness using interferometric images of the tear film (www.tearscience.com).
▸ Oculus Keratograph (OCULUS Optikgerate GmbH). This instrument, which came to market in 2012, is loaded with tear film scan software that measures tear quality and quantity non-invasively, and one model also acquires infrared photographs of the meibomian glands (www.oculus.de/us/sites/detail_ger.php?page=531).
▸ RPS InflammaDry Detector (Rapid Pathogen Screening, Inc.). This stick-like instrument, which came to market in 2013, identifies MMP-9, an inflammatory marker that is frequently elevated in DED patients’ tears (www.inflammadry.com).
▸ TearLab Osmolarity System (TearLab Corporation). This device, which came to market in 2009, provides information to clinicians and researchers evaluating potential DED patients. Specifically, it uses nanotechnology to accurately assess tear film osmolarity. Increased osmolarity is a widely recognized marker for DED (www.tearlab.com).
▸ TearScan MicroAssay System (Advanced Tear Diagnostics [ATD]). This instrument, which came to market in 2013, is a quantitative point-of-care lab-testing platform. ATD’s tests include (1) lactoferrin, a confirmatory test for aqueous deficient DED and (2) immunoglobulin E (IgE), a confirmatory test for the presence of an active allergen. (www.teardiagnostics.com/order).
▸ Cyclosporine A 0.05% (Restasis, Allergan). The drug, which received FDA approval in 2003, is a proven, effective therapy for inflammation-related aqueous tear deficiency and meibomian gland dysfunction (www.restasis.com).
▸ LipiFlow (TearScience). This device, which came to market in 2011, uses controlled heat on the inner and outer surfaces of the upper and lower eyelids to thin meibum. Then it uses pulsed pressure to open clogged meibomian glands and express the secretions (www.tearscience.com). It is used in conjunction with LipiView to diagnose and manage MGD.
▸ Phospholipid liposomal spray. This treatment, available from various manufacturers, uses liposomes, which are spherical nanoparticles that compose a lipid bilayer to efficiently deliver lipids to the eye. After these particles are applied to closed eyelids, they quickly migrate to the ocular surface. Benefits of liposome therapy: TBUT improvement and the reduction of lid-parallel conjunctival folds and lid margin swelling, says “The International Workshop on Meibomian Gland Dysfunction: Report of the Subcommittee on Management and Treatment of Meibomian Gland Dysfunction.”
▸ Proprietary warm compresses. Several are available to provide MGD relief. Simply type “warm compresses for eyes,” or “warm compresses for dry eye,” in your favorite search engine.
Currently, more than 500 products for DED treatment are undergoing FDA scrutiny.
To appreciate the potential financial impact of DED on optometry, the medical costs for each patient in the United States are estimated at $783 per year, reports Investigative Ophthalmology & Visual Science. The overall annual medical costs associated with DED are estimated at $3.84 billion per year.
In 1976, West Virginia passed the first legislation authorizing optometrists to prescribe medications for the treatment of glaucoma. This landmark legislation eventually went national, prompting the profession to play a major role in the prevention of vision loss in glaucoma patients. It is my hope the two reasons outlined above elicit a similar action by O.D.s to make diagnosing and treating DED a priority. Optometry is perfectly positioned to be the primary provider of care for DED. O.D.s who manage this condition can enhance patients’ vision, comfort and overall ocular wellness. This can be challenging, and at times frustrating, but successful management of DED can also be tremendously satisfying as well as beneficial to our practices. OM
Dr. Townsend practices in Canyon, Texas as part of a multi-location optometric group. He is an adjunct professor at the University of Houston College of Optometry and is president of the Ocular Surface Society of Optometry. E-mail him at email@example.com, or send comments to firstname.lastname@example.org.