dry eye

How Dry Am I: Making Sense of Dry Eye Disease

What the ITF and DEWS reports mean to optometrists.

BY ERNIE BOWLING, O.D., M.S., F.A.A.O., DIPL., Gadsden, Ala.
GREGG ERIC RUSSELL, O.D., F.A.A.O., DIPL., Marietta, GA

Every practicing optometrist has patients with dry eye disease (DED) walking into their clinic daily. This condition is rampant, almost endemic throughout the population and shows only mixed results when treated. We have all seen the effects of the disease on our patients' quality of life.

Dry eye has been shown to impact a patient's ability to read, to perform professional activities, to work on the computer and to safely drive during the day or night.¹ Patients have rated DED similar to moderate angina in terms of affecting their daily lives.² We have all been challenged with the diagnosis and have encountered frustration with the treatments.

Because of the vast number of practicing optometrists in the United States, we are uniquely situated to diagnose and treat dry eye disease. As the primary eye care professional, O.D.s are often the first to encounter the disorder and are able to make the diagnosis through case history and/or clinical signs. Unfortunately, many patients mistakenly equate dry eye as the presence of scratchy, watery and/or burning eyes, when in fact blurred vision is often the earliest presenting symptom.³ Indeed, these same patients have also become so accustomed to their condition that they may not even mention it during the course of an eye exam.

There is an abundance of literature on DED and ocular surface disease in scientific journals and trade publications. Making sense of all the information can be a burdensome task. How can we digest it all, especially when it seems some information is not evidence-based and is more testimonial than fact? Two publications have done a wonderful job of summarizing current thinking on dry eye and practicing clinicians can garner a great deal of valuable information on the diagnosis and treatment of DED.

Concensus at last

The first, the International Task Force (ITF) on Dry Eye, often referred to as the Delphi Panel, is a group of 17 ophthalmologists and two optometrists whose purpose was to come to a consensus on dry eye diagnosis and treatment.⁴ This group initially proposed changing the name of DED to "dysfunctional tear syndrome" as they felt this term more accurately reflected the pathophysiological events occurring in DED. While this term is probably more descriptive, the term dry eye is well recognized in scientific and lay writing and the term "dry eye disease" was used in the Report of the International Dry Eye Workshop.⁵

The ITF panel was polled on the clinical tests used to diagnose dry eye. Their top four picks included tear film break up time, sodium fluorescein, rose Bengal vital dye staining of the ocular surface and Schirmer's testing.⁵ These are in fact the same tests that are commonly (and easily) performed daily in our practices. While these experts do have at their disposal instruments that are cost prohibitive in a private practice setting, their initial diagnostic methodology involves some of the same tests all O.D.s can perform.

The DEWS Report

The seminal work on dry eye was published in April 2007 in the Ocular Surface journal.⁶ The 2007 report of the International Dry Eye Workshop (DEWS) is an encyclopedic review of dry eye disease. It was the product of a team of international experts who labored for over three years to compile an evidence-based review of the present state of knowledge for DED and the methods used to evaluate, diagnose and manage the disorder. There were a number of interesting items that merged from the research. Most noteworthy was an updated definition of dry eye, developed from new knowledge about the roles of tear film hyperosmolarity and ocular surface inflammation in DED and the effects of the disease on visual function. The new definition is as follows:

"Dry eye is a multifactorial disease of the tears and ocular surface that results in symptoms of discomfort, visual disturbance, and tear film instability with potential damage to the ocular surface. It is accompanied by increased osmolarity of the tear film and inflammation of the ocular surface."⁵

The inflammation question

The role of inflammation in dry eye moved to a prominent position in the new definition and pushed aside the debate of "aqueous deficiency versus evaporation." This definition reflects research showing there is an inflammatory component to DED and tear film osmolarity plays a very significant role.

What does that mean to us clinically in how we treat our patients? We may need to consider implementing anti-inflammatory therapy earlier in our management of the condition, including prescribing steroids and other topical or oral agents. Furthermore, it is likely that a commercially available tear osmometer will be available for private practices to measure tear film osmolarity.

DED is further recognized as a dysfunction of the lacrimal functional system, which is defined as an integrated system comprising the lacrimal glands, ocular surface (defined more specifically as consisting of the cornea, conjunctiva and meibomian glands) and lids, and the sensory and motor nerves that connect these tissues.⁷ In other words, it is not just the lacrimal system that needs attention, but the entire apparatus from gland to ocular surface. The function of this unit is to maintain the tear film's integrity by controlling the tear film's components.

Grading with Delphi

The Delphi Panel developed a DED severity grading scheme, using a grade of 1 for mild or episodic dry eye to a grade of 4 for severe or disabling and constant DED and correlated this symptomatology with objective signs. The ITF guidelines classify four severity levels of DED.

Level 1 includes mild to moderate symptoms and no signs, while level 2 denotes moderate to severe symptoms, tear film signs, and appearance of mild corneal and/or conjunctival staining. Levels 3 and 4 both demonstrate severe symptoms. Level 3 includes the presence of significant keratitis and a Level 4 case could include severe keratitis and/or corneal and conjunctival injury.

The Delphi Panel agreed upon treatment recommendations for each severity level. For the treatment of level 1 DED, mild to episodic, the panelists recommended educating the patient (remember, many patients are not aware of their condition), making environmental modifications such as blunting air ducts, or adding a humidifier, discussing and attempting to eliminate systemic medications that can cause dry eye like diuretics and antihistamines and using artificial tears and eye lid therapy. After all, dry eye is often accompanied by meibomian gland dysfunction. Additional stages of treatment get more intense as the severity of the disease worsens, with surgical treatments such as amniotic membrane transplants suggested at level 4.

Once diagnostics indicate moderate to severe symptoms, tear film signs and the appearance of staining, the guidelines point toward another level of treatment. If the patient is not satisfied with the artificial tear, or repetitive use of the tear is a concern due to the preservative (e.g. BAK) in the formulation, then a switch to unpreserved tears might provide benefit.

Recommended treatments

In fact, the DEWS report states that "for patients with moderate to severe dry eye disease, the absence of preservatives is of more critical importance than the particular polymeric agent used in ocular lubricants."⁸ The use of steroids, cyclosporine A and nutritional supplements might also foster improvement as indicated in the guidelines.

Omega-3 fatty acid intake has demonstrated a correlation to dry eye, so recommending an increase in omega-3 intake may be helpful.⁹ In fact, a supplement containing omega-3 has demonstrated potential efficacy for treatment of dry eye symptoms when subjects were exposed to the Controlled Adverse Environment.¹⁰ Treatment benefits of concomitant use of artificial tears with cyclosporine A has also been demonstrated in clinical study.¹¹

When a patient does not respond to any of the above treatments, the ITF guidelines recommend oral tetracyclines or punctal plugs as further steps in treatment. Doxycycline may be prescribed, and an ophthalmic solution of doxycyline 0.025% has demonstrated improvement in dry eye signs and symptoms in a phase II clinical trial.¹² This product remains in development, and may be a potential treatment option in dry eye management.

Research and design of punctal plug technologies also continue to evolve. Options in punctal plugs provide temporary, semi-permanent and permanent designs for punctal occlusion so that the clinician may assess the efficacy of punctal occlusion on a patient-by-patient basis. Moreover, the development of thermosensitive, adapting designs have eliminated the dependency on accurate sizing, although due caution should be exercised to avoid canaliculitis or other potential induced complications.

When the severity of dry eye reaches manifestation of severe keratitis and evident physical damage to the ocular surface (e.g. erosions, scarring), the ITF classifies the disease state as level 4. Treatment for this category can include measures such as moisture goggles or surgery. In general, all treatments falling below those recommended for level 4 should be exhausted prior to undergoing these more advanced steps.

The clinician's role

While researchers strive to discover and develop future treatments for dry eye disease, clinicians are left to determine the best course of action on an individualized basis. These guidelines are just that – a guide for the clinician to assist in the diagnosis and treatment regimen. However, they are not a substitute for clinical impression and case history. Ultimately, treatment decisions are left to the clinician and patient together. It is important to remember that the features of dry eye are those of a specific process and dry eye is a disease.¹³ Treat dry eye as you would any other disease process; by diagnosing the disease through history and clinical findings, prescribing appropriate treatment dependent on the presentation, and monitoring the effects of the therapy. Our patients deserve no less. OM

1. Miljanovic F, Dana R, Sullivan DA, Schaumberg DA. Impact of dry eye syndrome on vision-related quality of life. Am J Ophthalmo.l 2007 Mar;143:409-415.

2. Schiffman RM, Walt JG, Jacobsen G, et al. Utility assessment among patients with dry eye disease. Ophthalmology. 2003;110:1412–1419.

3. Latkany R. Dry eyes: etiology and management. Curr Opin Ophthalmol. 2008;19:287-291.

4. Behrens A, Doyle JJ, Stern L, et al. Dysfunctional tear syndrome. A Delphi approach to treatment recommendations. Cornea. 2006;25: 90-97.

5. Lemp MA, Baudouin C, Baum J, et al. The definition and classification of dry eye disease: Report of the Definition and Classification Subcommittee of the International Dry Eye Workshop (2007). Ocular Surf. 2007;75-92.

6. International Dry Eye Workshop. 2007 report of the International Dry Eye Workshop (DEWS). Ocular Surf. 2007;5:67-204.

7. Stern ME, Beuerman RW, Fox RI, et al. The pathology of dry eye: the interaction between the ocular surface and lacrimal glands. Cornea. 1998;17:584-589.

8. Pflugfelder SC, Geerling G, Kinoshita S, et al. Management and therapy of dry eye disease: Report of the Management and Therapy Subcommittee of the International Dry Eye Workshop. Ocular Surf. 2007; 5:163-178.

9. Miljanović B, Trivedi KA, Dana MR, et al. Relation between dietary n-4 and n-6 fatty acids and clinically diagnosed dry eye syndrome in women. Am J Clin Nutr. 2005; 82:887-893.

10. Pratt SG, Ousler GW, Schindelar M, et al. Evaluation of a novel dry eye oral supplement for the treatment of the signs and symptoms of dry eye in the controlled adverse environment (CAE) model. Invest Ophthalmol Vis Sci. 2005; 46: E-abstract 2047.

11. Sall KN, Cohen SM, Christensen MT, Stein JM. An evaluation of the efficacy of a cyclosporine-based dry eye therapy when used with marketed artificial tears as supportive therapy in dry eye. Eye Contact Lens. 2006;32: 21-26.

12. Ousler GW III, Power D, Schindelar M, et al. A phase II double-masked, randomized, parallel-group study to assess the safety and efficacy of ALTY-0501 (doxycycline 0.025% ophthalmic solution) in dry eye patients exposed to the controlled adverse environment (CAE). Invest Ophthalmol Vis Sci. 2008; 49 :E-abstract 102.

13. Lemp MA. Advances in understanding and managing dry eye disease. Am J Ophthalmol 2008, in press.

	Dr. Bowling is an associate professor and director of the primary eyecare service at the University of Alabama at Birmingham School of Optometry. E-mail him at ernie50@uab.edu.
	Dr. Russell practices at the Marietta Eye Clinic. He specializes in contact-lens fittings for patients who have keratoconus, corneal scars and refractive surgery complications. Contact him at (770) 427-8111.