TFOS DEWS II steering committee
By Helen Carter
The DEWS II Report has officially been released, outlining developments in the dry eye field over the past decade and providing global consensus on the disease.
It comprises 12 Tear Film and Ocular Surface Society (TFOS) Dry Eye Workshop II (DEWS II) sub-committee reports, resulting from an international evidence-based process that took 150 clinical and basic research experts from around the world, including 12 Australians, more than two years to complete.
The management and therapy report concludes that many treatments would benefit from further research to inform dry eye management, particularly in relation to applying therapies to patients with the major dry eye sub-types of aqueous deficiency and evaporative dry eye.
To help optometrists treat dry eye patients, the TFOS DEWS II Management and Therapy sub-committee, including Melbourne optometrist Dr Laura Downie, devised a ‘staged management algorithm.’
Dr Downie is a University of Melbourne senior lecturer in the Department of Optometry and Vision Sciences. ‘The algorithm outlines a step-wise approach to using various management and therapy options, based on current, best-available evidence, and is stratified according to dry eye severity,’ she told Australia Optometry.
‘Since publication of the original TFOS DEWS reports in 2007, there has been a dramatic increase in the number of management and therapy options for dry eye disease.
‘The current TFOS DEWS II Management and Therapy report references more than 1,000 publications.
‘Developments in the field over the past decade have included new ocular lubricants, in particular lipid-based eye-drops, autologous serum therapies and advancements in punctal plug designs.
‘The review also highlights areas for future research, where high quality intervention trials are currently lacking, in particular, a need for studies that determine the synergistic therapeutic actions of different therapies for managing dry eye disease,’ Dr Downie said.
Dr Laura Downie Image: Justin Malinowski
New dry eye definition
DEWS II also developed a new dry eye definition. It is ‘Dry eye is a multifactorial disease of the ocular surface characterised 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 aetiological roles.’
The first DEWS report was released in 2007. TFOS founder Dr David Sullivan said it was called the dry eye bible and its publication was a landmark event in the history of understanding and treatment of dry eye disease.
Ten years later, the TFOS DEWS II reports were published in The Ocular Surface on 20 July 2017 to update the definition, classification and diagnosis of dry eye disease, critically assess the aetiology, mechanism, distribution and global impact of the disorder, and address its management and therapy.
Australians on the DEWS II committees were Professor Fiona Stapleton, Professor Mark Willcox, Dr Laura Downie, Professor Nathan Efron, Professor Craig Woods, Dr Blanka Golebiowski, Dr Isabelle Jalbert, Dr Maria Markoulli, Professor Thomas Millar, Professor Eric Papas, Associate Professor James Brock and Dr Jason Ivanusic.
TFOS DEWS II sub-committee reports
TFOS DEWS II Management and Therapy Report undertook an evidence-based review of current dry eye therapies and management options including treatments for tear insufficiency, lid abnormalities, anti-inflammatory medications, surgical approaches, dietary modifications, environmental considerations and complementary therapies.
‘Following this extensive review it became clear that many of the treatments available for the management of dry eye disease lack the necessary Level 1 evidence to support their recommendation, often due to a lack of appropriate masking, randomisation or controls and in some cases due to issues with selection bias or inadequate sample size,’ the report’s abstract concluded.
‘Reflecting on all available evidence, a staged management algorithm was derived that presents a step-wise approach to implementing the various management and therapeutic options according to disease severity.
‘While this exercise indicated that differentiating between aqueous-deficient and evaporative dry eye disease was critical in selecting the most appropriate management strategy, it also highlighted challenges, based on the limited evidence currently available, in predicting relative benefits of specific management options, in managing the two dry eye disease subtypes.’
The report said more evidence was required to support the introduction and continued use of many of the treatment options currently available to manage dry eye disease, and to inform appropriate treatment starting points and understand treatment specificity in relation to dry eye disease subtype.
TFOS DEWS II Diagnostic Methodology report states: ‘Symptom screening with the DEQ-5 or OSDI confirms that a patient might have DED and triggers the diagnostic tests of (ideally non-invasive) break-up time, osmolarity and ocular surface staining with fluorescein and lissamine green (observing the cornea, conjunctiva and eyelid margin).
‘Prior to diagnosis, it is important to exclude conditions that can mimic DED with the aid of triaging questions. Meibomian gland dysfunction, lipid thickness/dynamics and tear volume assessment and their severity allow sub-classification of DED (predominantly evaporative or aqueous deficient) which informs the management of DED.’
TFOS DEWS II Epidemiology Report, a meta-analysis of published prevalence data, found prevalence of dry eye ranged from five to 50 per cent, prevalence of signs was higher and more variable than symptoms, prevalence increases with age, women have a higher prevalence and Asian ethnicity is a consistent risk factor.
The economic burden and impact on quality of life, vision, work productivity, psychological and physical pain are considerable.
TFOS DEWS II Tear Film Report says historically the tear film has been viewed as a three-layer sandwich composed of distinct liquid, aqueous and mucin layers but evidence supports the more contemporary two-phase model of the tear film, with a lipid layer overlaying a mucoaqueous phase.
TFOS DEWS II pathophysiology report states: ‘Its central mechanism is evaporative water loss leading to hyperosmolar tissue damage. Pain in dry eye is caused by tear hyperosmolarity, loss of lubrication, inflammatory mediators and neurosensory factors, while visual symptoms arise from tear and ocular surface irregularity.
‘Hybrid dry eye disease, with features of both aqueous deficiency and increased evaporation, is common and efforts should be made to determine the relative contribution of each form to the total picture. Practical methods are needed to measure tear evaporation in the clinic, and similarly, methods are needed to measure osmolarity at the tissue level, to better determine the severity of dry eye.’
TFOS DEWS II pain and sensation report states: ‘In dry eye disease, reduced tear secretion leads to inflammation and peripheral nerve damage. Inflammation causes sensitisation of polymodal and mechano-nociceptor nerve endings and an abnormal increase in cold thermoreceptor activity, altogether evoking dryness sensations and pain.
‘Long-term inflammation and nerve injury alter gene expression of ion channels and receptors at terminals and cell bodies of trigeminal ganglion and brainstem neurons, changing their excitability, connectivity and impulse firing.
‘Perpetuation of molecular, structural and functional disturbances in ocular sensory pathways ultimately leads to dysestesias and neuropathic pain referred to the eye surface. Pain can be assessed with a variety of questionnaires while the status of corneal nerves is evaluated with esthesiometry and with in vivo confocal microscopy.’