Ocular Surface Wellness: A New Idea for Eye Care
PART 2 The Road Ahead
Kelly K. Nichols, OD, MPH, PhD, FAAO
Although the diagnosis and treatment of ocular surface disease states has gained considerable attention in recent years, much less work has been devoted to preventing those conditions. But there is now a medical movement that seeks to push care in the direction of prevention as well as treatment of disease. This is reflected in this brief work on ocular surface wellness. In the first installment of this two-part series, I explored wellness and how it is approached in a variety of medical specialties, I also looked at the opportunity that exists within eye care to improve ocular surface health and function. The current installment looks at: (1) environmental and other challenges to ocular surface health; and (2) how those problems may be overcome.
I. The Ocular Surface and Its Environment
In today’s world, the surface of the human eye is challenged in multiple ways that are new to human experience. The human eye that evolved to support hunter-gatherers living in forests and grasslands must now cope with a radically different set of circumstances. This new environment includes contact lens wear, prolonged intense visual activity with focus maintained at near and intermediate distances, the adverse effects of ocular surgery, high rates of allergy, and drying from topical and systemic medication. Preserving healthy, comfortable vision for our patients requires a clear understanding of the environmental, physiological, and iatrogenic issues that challenge ocular surface health today.
Environmental Stresses
During the past two decades, advances in digital technology have revolutionized our world, but ocular health concerns surrounding their use have also arisen. Intense near- and intermediate-vision activities during extended use of digital screens can lead to a number of symptoms, including ocular dryness, blurred vision, and eye fatigue, which together have been termed “computer vision syndrome.”1
In addition, the indoor environments in which we work can induce ocular surface drying because they are typically low in humidity; and the decreased blink frequency occasioned by use of digital screens can further exacerbate ocular surface dryness.2-4 Dry eye conditions are particularly prevalent among individuals in occupations that require extended digital screen use.5 Even in schoolchildren, the use of devices with digital screens (eg, mobile phones) has become an important risk factor for dry eye disease.6
Ocular dryness symptoms account for reduced work performance and loss of productivity among workers who spend large amounts of time in front of digital displays.7 Patients for whom screen use may contribute to symptoms of dryness or visual fatigue can take steps to lessen these effects, such as improving ambient lighting, adjusting viewing distance and angle, taking frequent breaks, using artificial tears, periodically looking away from the screen, and making an effort to blink often.
Growing Prevalence of Allergy
The term allergic conjunctivitis encompasses seasonal, perennial, vernal, atopic, and giant papillary conjunctivitis. The most common forms are seasonal and perennial allergic conjunctivitis, which together comprise more than 98% of the ocular allergy in the US.8
The prevalence of allergic conjunctivitis, one of the most common anterior inflammatory disorders of the eye, has been on the rise globally during the past few decades. It is now estimated to affect between 15% and 40% of the US population.9-11 While generally mild, allergic conjunctivitis can also cause significant morbidity (Figure 1).11 Since a routine eye exam may not coincide with the season in which an allergic individual is symptomatic, it is important to include questions about allergy in the history and to differentiate allergy from other ocular surface conditions.
Figure 1 Signs of allergic conjunctivitis include hyperemia (top) and conjunctival edema (bottom). From: Luchs J. Multi-drug Treatment for Allergic Conjunctivitis. Refractive Eyecare 2008;12(8):1,30-31. Used with permission.
High Prevalence of Dry Eye
Dry eye disease is a multifactorial disorder of the tears and ocular surface characterized by symptoms of discomfort, tear film instability, and sometimes inflammation.12 Likely among the most common conditions encountered by eye care professionals, estimates of dry eye prevalence vary widely, from 7.4% to 33.7% worldwide.13-15 Even using a very restrictive definition of dry eye, the disease is reported to affect almost 5 million Americans 50 years and older; tens of millions more experience episodes of dry eye, typically when exposed to adverse environmental factors such as low humidity.16
Dry eye is often seen in conjunction with allergic conjunctivitis and other ocular surface disorders.9 Dry eye, allergic conjunctivitis, and blepharitis are inflammatory conditions that share a number of common symptoms, including discomfort, itching, dryness, and irritation.17
Risk factors for the development of dry eye include increasing age, female gender, autoimmune disease, hormonal imbalance, abnormal corneal innervation, vitamin deficiency, environmental stress, contact lens wear, medication use, and ophthalmic surgery.12 In addition to persistent symptoms of discomfort, dry eye can affect visual function and interfere with vision-related daily activities, causing a substantial reduction in perceived quality of life.18 Inconsistent and/or blurred vision is common among dry eye patients.19 Though transient, these symptoms can affect visual performance and workplace productivity.20
Prevalence of Blepharitis
Blepharitis (inflammation of the eyelids) is another common ocular surface disorder. It can affect patients of either sex and of any race or age. There is a dearth of epidemiological data about blepharitis, but surveys show that, on average, eye care practitioners see some form of blepharitis in at least 37% to 40% of their patients.21
Anterior blepharitis is most often related to bacterial overgrowth or Demodex mite infestation of the anterior lid margin.22 Posterior blepharitis, the most common form, is typically associated with meibomian gland dysfunction (MGD). MGD is the primary cause of evaporative dry eye and a frequent cause of contact lens intolerance.21,23 MGD is also an important contributing factor to ocular discomfort associated with digital screen use.24 Often neglected by patients and sometimes by clinicians, blepharitis can have significant impact on quality of life.
Contact Lens Wear
Contact lenses divide the tear film into pre- and post-lens compartments, thinning the lipid layer and increasing evaporative tear loss.25,26 Where the tear film thins at the lens edge, mucin spreading and lipid layer reformation can also be disturbed. In patients with preexisting tear film abnormalities such as inadequate tear volume or MGD, these lens-induced alterations may lead to dry eye.
Dry eye symptoms are extremely common among contact lens wearers. Of the approximately 35 million contact lens wearers in the US, about half have symptoms of dryness and discomfort.27-29 Contact lens wearers are 12 times more likely than people without vision correction and five times more likely than spectacles-wearers to report dry eye symptoms.30 Dryness and discomfort are regularly cited as the reasons for contact lens intolerance and discontinuation.31,32
Aging Population
The world’s elderly population has grown dramatically in the past century. A recent United Nations study reported that worldwide, the proportion of people aged 60 years or older increased from 9.2% in 1990 to 11.7% in 2013 and will continue to increase.33 In 2013, there were 841 million people aged 60 years or older; this number is expected to more than double in 2050 to more than 2 billion.
During the aging process, the ocular surface undergoes anatomical and physiological changes that may predispose older patients to dry eye. These changes include decreased tear volume and flow, increased osmolarity, tear film instability, and alterations in the composition of the meibomian lipids.34-36
Widespread Medication Use
Both topical and systemic medications may affect the ocular surface and cause signs and symptoms consistent with dry eye. Benzalkonium chloride, the most frequently used bactericidal preservative in ophthalmic preparations, has been reported to cause conjunctival and corneal epithelial cell changes, corneal epithelial barrier dysfunction, and tear film instability.37 In glaucoma patients, the use of preserved topical ophthalmic drugs is an important cause of dry eye signs and symptoms.38
In addition, certain classes of systemic medication may also increase the risk of dry eye symptoms, most likely by means of reduced lacrimal secretion. These medications may cause dryness: antihistamines, antianxiety medications, antidepressants, diuretics, and oral corticosteroids.39-41
In addition to the widespread use of medications, the long-term maintenance of ocular surface wellness is threatened in numerous ways: the prevalence of conditions such as dry eye, blepharitis, and allergic conjunctivitis; the intense visual tasking involved in so much of modern work and leisure; and even refractive solutions like contact lens wear and laser vision correction. All these factors, among others, highlight the importance of programs aimed at maintaining ocular surface wellness.
II: Opportunities for Eye Care Professionals
While there is clearly need to treat ocular surface conditions—and benefit to doing so proactively—implementation of ocular surface wellness programs face hurdles that must be overcome. Some of the challenges are basic. For example, we lack agreed upon diagnostic and therapeutic protocols. Beyond that, certain social and economic conditions constrain our efforts to achieve ocular surface wellness. In addition, the US healthcare system is not structured to easily embrace prevention and wellness. None of these are insurmountable, and significant opportunity exists to improve patient outcomes by proactively promoting ocular surface wellness with our patients and progress is being made to toward defining and achieving ocular surface wellness.
What Is a “Healthy” Ocular Surface?
While most eye care practitioners would likely agree that they know a healthy ocular surface when they see one, a quantitative definition of that condition remains elusive. Substituting “normal” for “well” or “healthy” begs the question, for we know that the ocular surface, like other body tissues, changes with age.42
If change and decline are normal over a lifetime, do the clinical parameters used to describe wellness or “health” have to be defined in terms of age? It would seem so. Given that change—and decline—is normal, and that we tend to identify the youthful state of the ocular surface as optimal, should we aim to return an older eye to that functional state? To what degree is such a transformation possible? These are questions that today have no clear answer.
Is a Youthful Ocular Surface the Goal?
Because age-related changes are often implicated in the development of ocular surface conditions, activities aimed at maintaining the integrity and function of ocular tissues can be seen as a form of anti-aging, a branch of medicine that enjoys considerable vogue at the moment.
Recreating a healthy ocular surface in an older patient would be, in effect, turning back the clock. While this is an attractive goal, it remains unclear if, how, and to what degree an older patient’s ocular surface can be made to function as it did when the patient was younger.
Nutritional studies provide some hope of ocular surface restoration, but other measures will be necessary.42,43 More importantly, protocols for helping to maintain “youthful” function of the ocular surface—that is, primary prevention—will have to be developed.
What Is the Etiology of Common Ocular Surface Diseases?
One of the most common factors known to disrupt ocular surface homeostasis is contact lens wear. Although symptoms of dryness and discomfort in contact lenses are acknowledged to be a major cause of contact lens dropout, we lack a definitive understanding of how and why contact lens discomfort arises in patients.44,45 The recent TFOS International Workshop on Contact Lens Discomfort identified and described a number of contributing factors but came up short on determining a definitive cause.44 Similar gaps exist in other aspects of our knowledge of ocular surface disease.
Identifying Ocular Surface Disease
The stresses of modern living challenge the ocular surface, even in young people. In today’s world, digital screens are ubiquitous, and the association between screen use and the signs and symptoms of ocular surface disease has been demonstrated in many studies, including studies of children.1,6,46
Such findings offer a stimulus to look for ocular surface issues across a wider swath of the patient age spectrum. These findings also underscore the importance of preserving ocular surface health in younger patients: a 19-year-old with dry eye needs to think about what she can do to preserve her ocular surface for at least another 50 or 60 years.
So why do eye care practitioners not make looking for ocular surface disease a universal part of eye care practice—as, for example, they do with glaucoma?
In addition to a lack of commonly accepted diagnostic protocols, practitioners may not appreciate the importance to patients of managing ocular surface disease. They may believe current treatments are costly, ineffective, or not adhered to by patients.
The picture is complicated by the fact that multiple conditions can produce similar ocular surface signs and symptoms. MGD, aqueous tear deficiency, systemic inflammatory conditions such as Sjogren’s syndrome, topical and systemic medications, blink defects, and other pathologic processes can all cause similar ocular surface signs and symptoms (Figure 2).12 Thus, clinicians must not only determine the presence of an ocular surface condition but also define its etiology, which in any given patient may be complex. No single diagnostic test—nor any widely agreed-upon sequence of tests—will accomplish this.
Figure 2 Lissamine green conjunctival staining: a classic sign of dry eye. From: Aldridge C. Protecting the Ocular Surface in Dry Eye Patients. Presented at SECO March 1, 2012. Photo courtesy Michael A. Lemp.
Eye care practitioners and clinical organizations are therefore challenged to develop screening and diagnostic algorithms based on the latest science, understanding that these will have to be modified as we learn more about the relevant disease states and as new diagnostic modalities and treatments become available. In addition to guiding effective patient management, these diagnostic and therapeutic regimens must also fit into busy physicians’ schedules and meet payers’ expectations.
Securing Reimbursement for Wellness Counseling
The structure of reimbursement for health care services in the US poses additional barriers to adopting a wellness approach to ocular surface care. Insurance payment for medical eye care most often takes the form of reimbursement for specific services or procedures. Payment for primary prevention activities—those that aim to keep ocular surface disease from occurring in healthy eyes—is today likely to be available only in the form of patient-paid fee-for-service.
Secondary prevention—the early-stage diagnosis and treatment of ocular surface conditions—may be reimbursed, but that presumes the doctor looks for and identifies ocular surface conditions in patients, many of whom may be in the office for other reasons and consider these additional services unnecessary.
III. The Road Ahead
Without a smooth, continuous tear film, light may not focus sharply on the retina. Ocular surface conditions may cause intermittent blurring and reduced contrast sensitivity that may interfere with leisure activities and workplace productivity.18-20 Preexisting dry eye can affect the visual outcomes and severity of symptoms following ocular surgery.47,48 Similarly, because of the demands that contact lens wear places on the ocular surface, maintaining a healthy tear film is important for comfort and visual performance in contact lenses.44,49,50
Ocular surface wellness is also important because patients care about how their eyes look. The cosmetic impact of conjunctival hyperemia, a sign in multiple ocular surface conditions, can be troubling for affected patients. In addition, eyelid margin disease can, over time, result in unattractive (and sometimes permanent) scarring and eyelash loss or misdirection. Efforts to maintain ocular surface wellness aim to help patients enjoy good vision, ocular comfort, and healthy-looking eyes.
Encouraging Wellness
The opportunity for improved patient outcomes through ocular surface wellness begins with us, eye care professionals. Here are some thoughts about what practitioners can do to encourage wellness.
Secondary prevention—finding and treating early-stage disease and managing risk factors—can be a starting point. To this end, the development of algorithms for screening, diagnosis, and management of ocular surface disease is critical.
Wellness implies active participation in maintaining and optimizing one’s state of health. Often, this means patients must change their behaviors. However, behavioral change when no significant symptoms are present requires the patient’s active buy-in and involvement. Physicians can often forge an alliance with patients by listening for clues about what is important to them—aesthetics, for example, or athletic performance—and this can guide messages about keeping eyes healthy. When early signs of ocular surface disease are present, illustrating them (eg, with slit lamp images) and showing patients the difference between a healthy ocular surface and their own can be motivating.
What Practitioners Can Do Today
Eye care practitioners must discuss and determine best practices for persuading patients of the “why” and instructing them on the “how” of maintaining eye health. Talking consistently to patients about small actions they can take to mitigate and/or prevent ocular surface issues will be valuable. Regular eyelid hygiene, optimization of indoor environments, frequent breaks from intense computer work, and proper care and replacement of contact lenses can all be discussed with patients before they experience bothersome ocular surface symptoms.
Ocular surface wellness is a novel and exciting idea, but it still needs fleshing out. Its scientific basis, already established, needs to be deepened; definitions must be created, and diagnostic and treatment protocols defined and validated. Protocols for achieving and sustaining ocular surface wellness, once defined, must be integrated into the training and continuing education of eye care practitioners. The underlying need for our patients is greater than these challenges.
Looking to the Future
Focusing on ocular surface wellness represents a long-term opportunity for eye care practitioners to proactively impact patient outcomes and help them see, look and feel their best. Having come far in recent years in the diagnosis and treatment of ocular surface conditions, we are now motivated to begin earlier and think farther into the future for each patient. More research, clearer protocols, and public communication are all needed. Progress will follow from sustained dialog about ocular surface wellness.
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| Kelly K. Nichols, OD, MPH, PhD, FAAO, is dean and professor of optometry at the University of Alabama at Birmingham School of Optometry. In addition, she serves as a medical adviser to the Sjögren’s Syndrome Foundation, is an executive board member of the Tear Film and Ocular Surface Society, a founding member of Ocular Surface Society of Optometry, and is on the editorial boards of Optometry and Vision Science and The Ocular Surface. |
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