Around 30 years ago, the increasing incidence of dry eye raised concerns all over the world, leading to its declaration as a disease.Multiple research initiatives have since been funded thanks to mutual efforts from both private and public sectors to determine the basis, define the parameters, and investigate the treatment of the disease.To date, this investment has not reduced the number of dry eye disease (DED) cases, in fact the incidence of the disease rose by 8–10% over the past decade. However, the answer to halting its growing prevalence may lie in the recent Tear Film Ocular Surface Society (TFOS) Dry Eye Workshop II (DEWS II) report series.The two-and-a-half-year, worldwide undertaking involved 150 clinical and basic research experts who utilised an evidence-based approach and a process of open communication, dialogue, and transparency to achieve a consensus concerning most aspects of the disease.This not only resulted in an updated definition of the disease and its pathologies, but it also helped paint a clearer picture of the effect DED was having worldwide and the possible causes of its increasing incidence. For example, a greater reliance on digital technology and the resultant extended hours spent staring at a screen is just one of the factors that has led to increased productivity loss and health insurance claims amounting to millions of dollars each year.In Australia alone, around one in five adults have experienced DED at some stage, while the long hours exposed to air conditioning and computer screens has meant that figure rises to nearly half of the office-based workforce.{{quote-A:R-W:450-I:2-Q: Nationally, approximately 4.9 million people, 3.2 million women and 1.7 million men, over the age of 50 years are estimated to suffer from moderate to severe dry eye -WHO:Kelly Nichols, Study Co-author from the University of Alabama-Birmingham School of Optometry}}A 2016 report published in Investigative Ophthalmology and Visual Science reported that DED is one of the most common reasons for eyecare visits in the US. However, while it causes negligible absenteeism among workers, it has been found to reduce workplace and non-job related performance by an average of 29%.“Nationally, approximately 4.9 million people, 3.2 million women and 1.7 million men, over the age of 50 years are estimated to suffer from moderate to severe dry eye, while tens of millions of Americans experience milder, episodic dry eye symptoms, which are often triggered by environmental factors such as the wind, low humidity, air conditioning and air pollution, or contact lens use,” study co-author Dr Kelly Nichols from the University of Alabama-Birmingham School of Optometry said.“Established risk factors for the development of dry eye include older age, fale sex, smoking, postmenopausal estrogen therapy, refractive surgery, vitamin A deficiency, and a diet low in omega-3 essential fatty acids.”Another contributing factor to DED’s increasing incidence is blue light exposure. As alluded to earlier, studies have shown around 60% of people worldwide spend more than six hours a day in front of an electronic digital device.Back home, the figures are even more concerning. The average Australian spends 9.5 hours, or one-third, of each day in front of screens, while office workers are exposed to harmful blue light for 11.4 hours a day. By contrast, the average Australian only gets 7.5 hours of sleep a night.Given these habits are unlikely to change, a consensus on the definition and treatment of DED has taken on extra significance.
Dry Eyes redefinedThe recent DEWS II report created a new definition for DED to address the dand for a more comprehensive and specific focus on the disease. Crucially, the inclusion of a ‘loss of homeostasis’ helped clarify that tear film hyperosmolarity and ocular surface inflammation have causal aetiological roles, along with the addition of neurosensory abnormalities.“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 etiological roles,” the report states.Following the release of the report, Dr J Daniel Nelson, chair of the TFOS DEWS II steering committee responsible for developing the specific aims and mission of the project, explained to online medical news website Medscape the importance of practitioners understanding the broad heterogeneity of the disease, saying: “I believe we do a great disservice by labelling patients who come in with dry eye complaints as having a dry eye, which often becomes the wastebasket term clinicians use when they do not know how else to explain a patient’s complaints of eye irritation, tearing, dryness, burning, and foreign body sensation.”DED has several hybrid forms, but the leading causes of evaporative and aqueous-deficient DED are Meibomian gland dysfunction (MGB), Sjögren and non-Sjögren lacrimal disease.However, according to Nelson, tear hyperosmolarity is the core mechanism of DED.“We’ve learned that osmolarity and inflammation are part of the aetiology of the disease, so treatment has to [be] aimed at treating inflammation to reduce osmolarity to return to a normal tear film,” he says.Hyperosmolarity causes damage to the ocular surface directly through inflammation, in turn leading to a cycle of events amounting to a ‘vicious circle’ in which a subsequent loss of lubrication between the globe and eyelids results in increased friction, and exacerbated symptoms. When accompanied by inflammatory mediators, tear hyperosmolarity causes damage to ocular surface microvilli, epithelial cells, glycocalyx, barrier function, and goblet cells, resulting in DED becoming self-perpetuating. Increased friction in DEDAnother point raised in the DEWS II report is for clinicians to investigate further the role of increased friction in DED and its subsequent effects, as inflammation of the ocular surface can be responsible for inhibiting lacrimal secretion and loss of epithelial barrier function on the ocular surface.The report also found the neuropathic pain is likely caused by cold thermoreceptors discharging nerve impulses at normal ocular surface tperatures. This response is associated with cooling, warming, or increased osmolarity, and triggers reflex basal tear production and blinking.However, restoring tear film homeostasis, is the ultimate goal in DED managent, as it helps to break the aforentioned ‘vicious circle’ and stops the progression of DED. Determining whether the major cause or causes of an individual’s DED pertains predominantly to aqueous tear deficiency or to evaporation – or both – is critical to selecting the most appropriate managent strategy.DEWS II states that current failures in resolving patient symptoms and signs of DED may relate more to a lack of success in determining and targeting the underlying nature or cause of a patient’s DED, rather than a failure of the treatment itself. Thus, the heterogeneity of the DED patient population mandates that any treatment plan needs to be based on the individual’s profiles, characteristics, and responses.“Dry eye is a challenging disease to diagnose and treat due the complexity, variability, and chronicity of the disease,” Optometry Times editorial advisory board mber Dr Leslie O’Dell says.“The [DEWS II] diagnosis section lays the groundwork on which to base our exams, including triaging the patient to differentiate dry eye disease from other ocular surface conditions. It then goes on to guide the clinician on the best methods for uncovering both the signs and the symptoms of dry eye.”Despite the complex nature of DED, the report also stressed that the creation of managent and treatment strategies that are not overly complicated for patients was of great importance, along with additional topical therapies that are effective and inexpensive. Treatment AdvancesLeading the companies’ charge to tackle the probl of treating DED is the global biotechnology company Shire. Recently, it attpted to secure approval in Europe to distribute its DED drug lifitegrast (trade name Xiidra), in the hope of becoming the first company to release a new class of drugs to address signs and symptoms of the condition.The drug, which has already received FDA approval in the US, is expected to generate sales of more than US$1 billion (AU$1.27 b) if it makes it to market.“This submission is another important milestone for lifitegrast and the millions of patients living with dry eye disease,” Dr Howard Mayer, Shire’s Head of Clinical Development said.“Shire is committed to continued innovation in ophthalmics, where there are opportunities to address unmet needs and improve the lives of patients.”{{quote-A:L-W:470-I:24-Q: Lacritin is largely released into tears by acinar cells of the lacrimal gland, although it is also produced by other cells, including those of the meibomian gland -WHO:Gordon Laurie, Team Leader Professor}}As a lymphocyte function-associated antigen-1 (LFA-1) antagonist, lifitegrast is the first medication in a new class of drugs. It works by binding to the integrin LFA-1, a cell-surface protein found on leukocytes. It then blocks the interaction of LFA-1 with its cognate ligand intercellular adhesion molecule-1 (ICAM-1), which plays a prominent role in ocular surface inflammation.In clinical studies involving more than 2,500 patients, lifitegrast improved DED symptoms as measured by patient reported eye dryness score (EDS) and, in three of the four studies, it also improved the objective signs of dry eye disease, which were measured using corneal staining.However, it is not the only new treatment entering the race to treat this elusive disease. A novel topical synthetic peptide called lacritin by US-based TearSolutions has also undergone clinical development for the treatment of DED.A naturally occurring eye-selective tear glycoprotein, lacritin has been formulated as a topical medicine to stimulate basal tear secretion and promote wound healing. It is also believed to restore the reduced ocular surface cell population to normal levels.“Lacritin is largely released into tears by acinar cells of the lacrimal gland, although it is also produced by other cells, including those of the meibomian gland,” Dr Gordon Laurie, professor of cell biology and ophthalmology at the University of Virginia, said. Laurie discovered the healing potential of the agent in 2001 and co-founded TearSolutions to develop the drug.“Lacritin has the same properties as the parent molecule, and unlike all existing therapies for dry eye disease, appears to address an underlying cause of the disorder rather than a downstream consequence. Analogous to insulin treatment for diabetes, it essentially represents a replacent therapy to correct an existing deficiency and for that reason, we believe it holds exciting promise as a very safe and effective therapy,” Laurie added.Meanwhile, a team of scientists from the Technical University of Munich (TUM) is developing a lubricant derived from pigs’ stomachs as a solution to dry eyes resulting from long-term contact lens use. Mucin MUC5AC is a molecule that lubricates the surface of the eye, and not only is it found in tears, but also the stomach and intestines as well. It has the ability to bind together water enough to moisturise the surface of the eyes. For religious reasons, the porcine source may need a substitute if a universally acceptable product is to be realised.However, while there are other synthetic lubricants available in the market, such as hyaluronic acid, the TUM researchers say most formulations don’t occur naturally in the eye, and therefore need to be applied multiple times while contact lenses are worn.“Most of the mucins available commercially that are already used for the treatment of oral dryness, have lost exactly this ability. We were able to donstrate this in a series of experiments that these commercial mucins are therefore not suitable for treating dry eyes,” team leader Professor Oliver Lieleg explained.{{quote-A:R-W:450-Q: The escalating incidence of DED has led to an increasing array of DED diagnostic equipment and devices, as well as new treatment options for optometrists and patients. Over the page we provide an at-a-glance guide to the DED market leaders. -WHO:Dry eye market leaders}}Testing their formula on pig eyes, the team’s lubricant formula showed no signs of tissue damage, while soaking the contact lens in the pig-derived mucin formula overnight is enough to prevent dry eye-related probls.“We showed that the mucin passively absorbs to the contact lens material and forms a lubricating layer between the contact lens and the cornea,” study author Mr Benjamin Winkeljann said.The team believes the main benefit of their research is the close association of their mucin formula to the natural substance found in tear fluid and would not require repeated applications.Although human trials are still some way off, the team is considering doing further tests on other laboratory animals. The Future for DEDWhile there is still no cure-all for DED, intensive R&D efforts continue in the search for the best treatment and managent strategy for DED. The DEWS II report made significant progress towards addressing DED, and a better understanding of the pathophysiology of the disease has been gained over the past 20 years.The challenge now is for the next 20 to provide an even brighter outlook for future generations of DED sufferers.
Gallery: Aussie suppliers with Dry Eye products
LIPISCAN
The Tear Science LipiScan images meibomian glands with Dynamic Meibomian Imaging (DMI), which simultaneously ploys Dynamic Reflected Illumination and Adaptive High-definition Transillumination. Each technology generates its own independent image of glands, which is then processed, displayed, and combined to provide a more accurate visualisation of gland structure. Glare is virtually eliminated and lid thickness is factored in, significantly reducing interpretation errors.
Preservative-free HYLO-FRESH (sodium hyaluronate 0.1% w/v, 10mL), delivers lubrication for dry eyes of moderate or medium severity, while the more viscous HYLO-FORTE (0.2% sodium hyaluronate w/v, 10mL) is ideal for the treatment of severe or chronic dry eye. HYLO drops provide a systatic approach to dry eye treatment through the unique COMOD (COntinuous MOno Dose) application syst, delivering at least 300 sterile drops per bottle. Both can be used with all contact lenses, are suitable for post-surgery use, and are phosphate-free.
The Eye Doctor Mask is a hot eye compress designed to treat meibomian gland dysfunction, the leading cause of dry eyes disease. After heating the mask in the microwave it’s placed over the eyes for 7–10 minutes. The comfort strap can be adjusted to suit the individual and the mask is reusable and can be stored in a handy travel pouch. It has a washable cover for hygiene purposes and is an essential first step for anyone suffering from dry eye symptoms. This mask was even voted as #1 product in patient and optician preference test and also winner of Queen Elizabeth Award for Innovation.
Utilising patented VTP technology the Tear Science LipiFlow applies heat and pressure to the inner eyelid, optimising its ability to heat and clear the meibomian glands and safely rove gland obstructions and stagnant gland contents.Delivered through the LipiFlow Activator, VTP technology simultaneously maximises results and minimises discomfort. Patented vectored heat and adaptive force equalisation targets the pulse, heat, and pressure on the meibomian glands to maximize effectiveness. Therapeutic motion rolls from base to lid margin releasing stagnant contents from the glands.
The Dry Eye Relief Mask (DERM) is an at-home patient treatment and is an entry level solution for immediate dry eye relief. The mask contains silica beads which naturally attract moisture from the air and release it when heated in a microwave. Unlike wheat bags there are no mould issues. Heating the mask as directed on the packet will provide soothing moist-heat relief for 4-6 minutes. Applying a moistened disposable cotton liner (included with every DERM) to the mask prior to heating will extend the treatment to 7-9 minutes. DERM is hypoallergenic and can also be used to create cold therapies for allergy relief. A washable cover is also available.
The OCULUS K5M is an advanced corneal topographer with a colour camera optimised for external imaging. It can help to accurately diagnose DED origins and document the findings in the Jenvis Dry Eye Report, which roves guesswork because the results point to the treatment regime to undertake for each patient. Once treatment is complete the K5M can compare results to evaluate the success of the treatment.
The summarised results in the Jenvis Dry Eye Report can be printed and given to, or ailed to your patient and other medical professionals. The K5M can image meibography, NIKBUT (non-invasive tear break time), Tear Meniscus Height, Lipid Layer, OSDI or McMonnies Dry Eye Questionnaire and automatically quantify Bulbar Redness.
Protective eye drops ideal for mild to moderate dry eye sufferers, including computer users, the elderly or long-term medication users. They are preservative-free in the eye and safe to use with contact lenses. Blink Intensive Tears improve tear film stability with a unique moisture retaining formula containing polyethylene glycol 400 and sodium hyaluronate (HA 0.20%).
SYSTANE GEL DROPS Lubricant Eye Gel is for night time protection and offers the thickest gel formulation to coat the eye with a strong layer of dry eye symptom protection. It provides your patient with long-lasting protection while they sleep. Available in 10mL bottles and can be used in conjunction with SYSTANE ULTRA Lubricating Eye Drops or SYSTANE BALANCE Lubricant Eye Drops for extra relief.
The ICP Tearscope is a Tear Film Screening device for analysis of the layers and stability. It analyses Tear Break Up Time – with or without fluorescein staining, as well as grading lipid layer thickness and meniscus height. The ICP Tearscope is a light-weight hand held device attached to an iPad.
VitA-POS (retinol palmitate 138 μg/g, 5g) is a smooth, preservative and phosphate-free eye ointment containing Vitamin A for night-time relief of dry eye. It stabilises the tear film and protects the ocular surface by preventing evaporation during sleep, and spreads easily over the ocular surface.
The ICP Ocular Surface Analyser is a Slit Lamp mountable multi-functional device to analyse the lacrimal layers and stability, and advanced infrared meibography imaging with automated detection and quantification of meibomian glands. It delivers comprehensive and convenient scales and classification reports for differentiation of evaporative DED and Meibomian Gland Dysfunction (MGD). Reports include lipid layer thickness, tear meniscus height, non-invasive tear break up time (NIBUT), analysis and classification of meibomian gland absence.
One in two contact wearers suffer from dry eye symptom; Blink Contacts eye drops contain 0.15% sodium hyaluronate that provides long-lasting moisture to both the lens and eye. Gentle preservative that helps maintain corneal integrity for healthy lens wear and are suitable for all soft and hard contact lens wearers, particularly during extended wear.
SYSTANE BALANCE Lubricant Eye Drops help support and restore your patient’s delicate lipid layer by replenishing essential moisture to eyes. This clinical-strength intensive therapy provides lasting relief from moderate to severe symptoms of dry eye. Available in 10 mL bottles for home or on the go.
The Blephasteam warming goggles heat up to 42 degrees over a period of 15 minutes, with the treatment taking just 10 minutes to complete. The Blephasteam requires disposable rings, which you wet with a saline solution to create a humid environment preventing dryness during the treatment. Meibomian gland expression immediately post Blephatseam treatment is advised, in an effort to elicit clear oil from the glands.
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