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A New Paradigm for Dry Eye The Academic to the Pragmatic Donald R. Korb, O.D. Boston, MA American Academy of Optometry Phoenix, AZ, October 2012 2-Hour Course ABSTRACT MGD is the leading cause of dry eye. A new model for the Dry Eye Cascade, including proposed mechanisms for how hyposecretory MGD, frequently nonobvious, cascades in to anatomical and atrophic changes of the ocular surface and adnexa which ultimately obscure the root cause of the dry eye − MGD. Clinical treatment and prevention are also addressed. SYNOPSIS Status of Dry Eye: Dry eye is the leading reason for visits to optometrists and ophthalmologists in the US. Dry eye is also the leading cause of contact lens intolerance leading to discontinuation of contact lens wearing. Treatment of dry eye has proven to be less than optimal. A New Direction for Dry Eye: A change in direction for the understanding of dry eye etiology and treatment was highlighted by the 2011 Report of the International Workshop on Meibomian Gland Dysfunction summary statement: “MGD may well be the leading cause of dry eye disease throughout the world.” (IOVS, 2011) This dramatic shift from the traditional aqueous and mucous-based models for dry eye to inclusion and emphasis of meibomian gland dysfunction resulted in an explosion of interest and research and qualifies as a true paradigm shift, as defined by the nomenclator of the term paradigm shift, Thomas S. Kuhn 1 LECTURE FOCI This lecture will present: The evidence for supporting this new paradigm of dry eye etiology, diagnosis and treatment, including the ever-expanding role of meibomian gland dysfunction and obstruction, and a new clinical entity, Non Obvious Obstructive Meibomian Gland Dysfunction (NOMGD). NOMGD has particular relevance to contact lens practice. A recently introduced diagnostic instrument for meibomian gland evaluation, which has allowed the evaluation and quantification of individual meibomian gland functionality and correlations to ocular symptoms and signs. Diagnostic methods including recently approved FDA diagnostic modalities. Emphasis will be placed on how this research provides a practical clinical approach for the diagnosis and management of dry eye patients in clinical practice. The relevance of NOMGD to the tear film and to lid wiper epitheliopathy allowing an understanding of how this new paradigm relates to dry eye etiology, pathogenesis, prevention and treatment. The relevance of the Line of Marx Dichotomies and anomalous findings encountered in dry eye conditions and disease – particularly aqueous vs evaporative dry eye Reimbursement and Coding The author’s new model for the Dry Eye Cascade, including a proposed mechanism of action to explain how minimal hyposecretory MGD, frequently non obvious, cascades in to anatomical and atrophic changes of the lids, meibomian glands, cornea, mucous secretory system and lacrimal gland until the magnitude of the changes obscure the root cause − meibomian gland obstruction. This model provides an understanding for the treatment and prevention of the most frequently encountered − the vast majority of dry eye. 2 Dry Eye Why do we care about Dry Eye? High prevalence Rapidly changing non-blinking environment with ever increasing use of electronic mobile media and computers Average age of onset is decreasing due to lifestyle - now includes children A public health issue Aging population Dietary concerns Contact lens wear Surgical outcomes - Lasik - Aphakia Dry eye has come looking for us…. With today’s lifestyle we cannot ignore dry eye. Definition: “Dry eye is a multi-factorial 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.” (DEWS report 2007) Etiopathogenic classification of dry eye – the 2007 DEWS report The contemporary model of dry eye was established by the 2007 DEWS report. ○ Systemic, behavioral, and environmental factors ○ Aqueous deficient dry eye vs. evaporative dry eye The role of inflammation o Is inflammation the cause of dry eye? o Is inflammation a sequela of many dry eye states? The role of autoimmune disease Meibomian Gland Dysfunction (MGD) Definition: "Meibomian gland dysfunction is a chronic, diffuse abnormality of the meibomian glands, commonly characterized by terminal duct obstruction and/or qualitative/quantitative changes in the glandular secretion. This may result in alteration of the tear film, symptoms of eye irritation, clinically apparent inflammation, and ocular surface disease.” (Report of the International Workshop on Meibomian Gland Dysfunction, IOVS, 2011) 3 Diagnosis and Classification of MGD Normal Hypersecretion (seborrheic) Obstructive MGD o Hyposecretion o Frequently non obvious Inflammatory MGD (pouting & plugging) Infective MGD (glands and/or lids) However, specific classification and diagnosis of MGD is rarely practiced due to a combination of factors including less than precise definitions for the types of MGD, the lack of instrumentation providing quantitative data, and the highly subjective methods of evaluation. These problems have prevented comprehensive diagnosis of MGD and the specific type of MGD, resulting in an under appreciation of the role of MGD in dry eye conditions and frequently inadequate treatment. Meibomian Glands – New Information and a New Expanding Role Key statement: “MGD may well be the leading cause of dry eye disease throughout the world.” Requires understanding of definition of MGD and MG functionality Meibomian Gland Function and Functionality o Functions of meibomian glands – minimize evaporation, tear film stability, vision, lubrication o Concept of a functional meibomian gland o How is MG functionality determined and quantified? o Meibomian gland secretion dependent upon blinking o What is MGD? A practical definition o Development of instrumentation for diagnosis of MG functionality and quantification o Specific MG activity at any given time? o Correlation between numbers of MG yielding liquid secretion (MGYLS) to dry eye symptoms? o The mean number of meibomian glands yielding liquid secretion (MGYLS) in nasal, central & temporal regions of the lower eyelid – all areas are not equal – a surprising finding o Time required for a single optimally secreting MG to recover after being drained of available oil o Diurnal variations in MG yielding liquid secretion o Variations in meibomian excreta with expression and the force of expression 4 Lid Wiper Epitheliopathy (LWE) – Frequently the Missing Link Definition: Lid Wiper is that aspect of the marginal conjunctiva of the upper eyelid that wipes the ocular surfaces during blinking A missing link in dry eye diagnosis, treatment and contact lens comfort Windshield wiper analogy Prevalence Diagnosis and grading of LWE o The use of stains in diagnosis Correlation of LWE to dry eye signs and symptoms Evidence based medicine for LWE – the studies Causative factors of LWE – inflammation, lubrication, mechanical The role of the lid wiper in ocular sensation and symptoms The lid wiper and lid wiper epitheliopathy in contact lens practice The role of the lid wiper in exacerbating dry eye and inflammation Treatment of LWE FOCUS ON LUBRICITY OF TEAR FILM AND LWE History – Symptoms The Gold Standard for dry eye diagnosis Survey of preferred tests for diagnosis of the tear film and dry eye. (Korb, Cornea 19;483-6, 2000) OSDI questionnaire Speed questionnaire THE LINE OF MARX – A NEW AREA Role Diagnostic Value Treatment The Role of Interferometry Instrumentation – Interferometers The LipiView – A new computerized interferometer Measurement of lipid layer thickness and characteristics Correlation of lipid layer thickness to dry eye symptoms Correlation to meibomian gland expressibility and function Role in diagnosis and treatment 5 Tests for Dry Eye History Break-up time Staining Schirmer Meibomian gland functionality Meniscus height Lipcof Lipid layer thickness Other – over 20 Meibomian Gland Obstruction Obstruction of the meibomian gland ducts and orifices results from keratinized epithelial cells and secretory material aggregating in keratotic clusters, altering MG secretion & the tear film. Bacterial proliferation occurs in the desquamated cells of excretory pathways of the meibomian glands. Release bacteria & toxic products into tear film, resulting in: o Inflamed and red eyes o Infection o Reoccurring inflamed – infective states post antibiotic-steroid treatment suggests MGD Expanded classification and understanding of MGD should include: o Obstructive MGD without obvious inflammation but with signs of MGD o Non Obvious Obstructive MGD, possibly the most common form of MGD. Requires physical expression for Dx The paradigm shift in our understanding of Dry Eye is the result of the Tear Film and Ocular Surface Society’s recognition of the role of MGD in 2008, and the 2011 Report of the International Workshop on Meibomian Gland Dysfunction of this prestigious International Tear Film and Ocular Surface Society: 6 Treatment of MGD 1. Replace the meibomian gland secretions Lipid Replacement Drops – Systane Balance 2. Increase efficacy of meibomian glands & meibomian gland secretions Warm compresses (WC) Profiles for anterior and posterior lid temperature in WC treatment Scrubs of lid margins Expression – office treatment Limit of expression = PAIN ○ Limits of acceptable pressure in PSI ○ Pain limits specific to individual Self-expression Commercially available devices for MG treatment Role of blinking Medications – topical and systemic New treatments 2011 – FDA approval of LipiFlow Coding – Reimbursement Use of Codes Private Pay THE DRY EYE CASCADE – A NEW PARADIGM The author’s new paradigm – the theoretical and practical framework for understanding and treating the dry eye cascade: Summary – The Dry Eye Cascade is initiated by a decrease in meibomian gland functionality, resulting in a decrease in lipid secretion and resulting lipid layer thickness and quality. When the rate of evaporation of the aqueous exceeds that threshold required to maintain tear film stability, a series of sequelae result, with dry eye as an end point. 7 IMPLICATIONS OF MGD DRY EYE CASCADE & Stasis – Obstruction NON – OBVIOUS MGD Decrease in lipid secretions Evaporation increases Decrease in aqueous layer thickness Unstable tear film Sjögren’s Syndrome JRA Lubricity compromised Microtrauma Lid Wiper Epitheliopathy Triple Response of Lewis Inflammation Ocular surface compromised Dry eye Inflammation Sequelae of a compromised lipid layer Sequelae of a compromised lipid layer Visible changes Not Visible Changes – Specular Microscopy – 800 X Inflammation Cornea: Cells altered, nerve density, branching, tortuosity, neuromas, dendritic cells Palpebral and bulbar conjunctivitis Lids: Fibrosis, inflammatory cells, MG damage Anatomical changes to external surfaces, lid margins, Line of Marx SEVERE INTERNAL INFLAMMATION, FIBROSIS & ATROPHY Sequelae of a compromised lipid layer Does lacrimal gland up-regulate, overwork leading to atrophy ? Diabetic & adrenal analogue Treat MGD early to: Prevent visible and non-visible lid and corneal changes Prevent MGD & Dry Eye 8 SUMMARY of DRY EYE CASCADE Lipid deficiency & not aqueous deficiency is usually the catalyst for the DRY EYE & inflammatory cascade. Backward to conventional models and treatment MGD and MG OBSTRUCTION may be obvious or non-obvious, most frequently non-obvious, particularly in contact lens practice. Stasis and obstruction of the meibomian glands leads to decreased secretion and increased evaporation with the sequela of dry eye. Dx of MG functionality requires expression – new metrics Sequelae and mechanism of action of MGD – MGO over years Stasis and Obstruction ↓ Decrease in lipid ↓ Increases evaporation of aqueous ↓ Compromises tear film thickness and lubricity ↓ Leads to microtrauma and LWE ↓ Inflammation of Ocular Surface and Lid Wiper ↓ Inflammatory cascade ↓ Conjunctivae & posterior blepharitis ↓ Compromised conjunctiva – infection from pathogens – staph ↓ Sequelae – complex disease and unable to Dx root cause ↓ Anatomical changes to external surfaces, lid margins, Line of Marx ↓ Non Visible Changes – Specular Microscopy – 800 X ↓ Does lacrimal gland up-regulate, overwork & atrophy? 9 Maximizing the function of the meibomian glands Treat all blepharitis – treat cause Tx of MG & MGD should be started early – dental analogy Role of drugs Heating – lid hyperthermia not ideal but mandatory Tx Forceful expression 2011 – New Modality – FDA approved LipiFlow 10