DEWS II: Dry eye disease revisited

Earlier this year, the Tear Film & Ocular Surface Society (TFOS) presented DEWS II, the conclusions and recommendations of the TFOS Dry Eye Workshop II. This report was compiled with the goal of setting a global consensus on the many factors of dry eye disease (DED), and is an update of the original TFOS DEWS report released 10 years ago.

“TFOS DEWS II involved the efforts of 150 clinical and basic research experts from around the world, who utilized an evidence-based approach and a process of open communication, dialogue, and transparency to increase our understanding of dry eye disease,” said the workshop organizer David A. Sullivan, MS, PhD, associate professor of ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear, Boston, MA.

Dry eye disease is a worldwide problem that affects more than 30 million people in the United States. It is one of the most common causes of patient visits to eye care practitioners.

According to J. Daniel Nelson, MD, FACS, FARVO, workshop chair, the objectives of TFOS DEWS II were to update the definition, classification, and diagnosis of DED; critically evaluate its epidemiology, pathophysiology, mechanism, and impact; address management and therapy; and develop recommendations for clinical trial design to properly evaluate pharmaceutical treatments.

In the new report, dry eye is redefined as “…a multifactorial disease of the ocular surface characterized by a loss of homeostasis of the tear film, and accompanied by ocular symptoms, in which tear film instability and hyperosmolarity, ocular surface inflammation and damage, and neurosensory abnormalities play etiological roles.”

The addition of the phrases “loss of homeostasis” and “neurosensory abnormalities” are pivotal in the revised definition, and were included because they are thought to contribute to the common mismatch between the signs and symptoms of dry eye.

“Inclusion of the phrase ‘loss of homeostasis’ is novel, and this definition clarified, based on recent peer-reviewed evidence, that tear film hyperosmolarity and ocular surface inflammation have causal etiologic roles, along with the addition of neurosensory abnormalities (contributing to the common mismatch between signs and symptoms),” noted the authors.

The role of sex, gender, and hormones is clarified, although further research is needed to determine the effects and mechanisms of these factors on eye health and disease.

“While sex, gender, and hormones play a major role in the regulation of the ocular surface and adnexal tissues, and in the difference in DED prevalence between men and women, further research is needed to clarify the precise nature, extent, and mechanisms of these sex, gender, and endocrine effects on the eye in health and disease. A deeper understanding of these issues may result in improved, more tailored and appropriate options for the treatment of DED,” wrote the authors.

Definitive conclusions regarding the epidemiology of DED remain challenging. The effects of age, tear film composition, tear thickness, lid differences, corneal or conjunctival sensitivity, ethnicity, and sex must also be studied further.

The influence of tear film on DED is in need of clarification, according to the authors. Specifically, the biochemistry and identification of new markers used to diagnose, predict, and treat DED are needed. Changes in tear proteins occur in DED, but no validation of specific proteins or changes has occurred.

The role of pain and sensation are included, with a particular stress on cold thermoreceptors, which respond to warming, cooling, and increases in osmolarity. This may contribute to the control of basal tear production and blinking. Thus, noted the authors, further study of treatment strategies that involve cold receptors is called for.

The role of iatrogenic dry eye is outlined, and DEWS II cited the numerous contributors to dry eye such as topical and systemic medications, contact lenses, ophthalmic surgeries, and nonsurgical procedures.

The DEWS II report recommended a diagnostic methodology for dry eye.

“If DED is suspected, a positive result to a screening questionnaire such as the 5-item Dry Eye Questionnaire or the Ocular Surface Disease Index should trigger further evaluation, with tear break-up time (noninvasive methods preferred), tear film osmolarity determination, and ocular surface staining (that includes the cornea, conjunctiva, and lid margin) with fluorescein and lissamine green. Identification of a disruption in tear film homeostasis with these tests, allows a diagnosis of dry eye to be made,” wrote the authors.

The goal of management and therapy of dry eye should be the restoration of tear film homeostasis. An appropriate management strategy depends on the accurate determination of the causes of each patient’s DED, including aqueous tear deficiency or evaporative causes.

Finally, treatment individualization in patients with DED is imperative.

“Although staged management and treatment recommendations are presented, the heterogeneity of the DED patient population mandates that practitioners manage and treat patients based on individual profiles, characteristics, and responses,” they wrote.

The TFOS DEWS II report is published by The Ocular Surface and distributed to scientists, clinicians, and patients worldwide. A downloadable version of the document and additional material will be available on the TFOS website: www.TearFilm.org. Translations of the report will be offered in numerous languages, including English, Chinese, French, German, Italian, Korean, Spanish, and Vietnamese.