C linical management of ocular surface disease, and particularly dry eye disease, remains challenging, and research plays a vital role in guiding the field by providing scientific evidence to support recommendations for optimal patient care. A significant milestone in the history of dry eye research was the publication of the National Eye Institute/Industry Workshop in 1995, 1 followed by the further impactful consensus workshops of the Tear Film and Ocular Surface Society (TFOS) that consolidated the latest peer-reviewed evidence to offer clinical guidance and help set future directions for research and development within the field. It has been 17 years since the publication of the first TFOS Dry Eye Workshop (DEWS) 2 and 7 years since the publication of the second workshop, TFOS DEWS II, 3 and it is clear that the dry eye field continues to witness growing interest in the management of dry eye (Fig. 1).The move in the last 30 years away from the concept of dry eye as simply reflecting a low volume of aqueous tears has aligned with recognition of the importance of the quality of the tear film. This has driven an immense increase in activity for researchers and for clinicians delivering care to patients and, similarly in the response from industry, in attempting to address the needs of dry eye patients and their clinicians.Based on existing evidence, TFOS DEWS II subclassified dry eye into aqueous and evaporative components, where aqueous deficiency reflects dysfunction of the lacrimal gland, and evaporative dry eye recognizes other causes that affect the tear film quality. 3 This includes issues with the ability of the ocular surface to support a stable fluid layer or most often relates to dysfunction of the meibomian glands that are responsible for producing the thin but vital superficial tear lipid layer. Ultimately, dry eye management requires conscious consideration of the risk factors, both nonmodifiable and modifiable, to help raise awareness and educate patients and their caregivers about dry eye and so that appropriate recommendations can be provided on possible changes particularly in the case of modifiable risk factors. 4 Diagnostic criteria for dry eye have been clearly defined, 5 allowing a uniform approach to be taken to assessing patients and ensuring consistency in the advice given to patients. These criteria identify patients whose ocular surface has entered a self-perpetuating cycle of tear film instability, hyperevaporation, hyperosmolarity, ocular surface damage, and inflammation referred to as the "vicious circle of dry eye." 6 Treatments then aim to interrupt this cycle to allow restoration of the tear film and ocular surface homeostasis. Subsequent dry eye subtype classification at this point becomes critical in helping to best identify the cause(s) of the dry eye in order to offer one or more appropriate therapies to address identified deficiencies. 4 The scope of dry eye disease research is broad, ranging from understanding its epidemiology and risk factors, and its pathophysiology, to re...
