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Understanding dry feeling eyes. Diagnosis and Treatment Gunter Wong, BSc(Hons)Optometry, MOptometry, PhD Training Manager, Asia Pacific 2009.10.02-CN1396 Content – understanding dry feeling eyes • Definition and incident • Physiology of the eye •Etiology and diagnosis •Management 2009.10.02-CN1396 Dry Eye Syndrome (DES) y y y ( ) A team of international experts collectively defined dry eye syndrome as: Dry eye is a multifactor 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.1 2009.10.02-CN1396 Reference 1. Report of the International Dry Eye Workshop. Ocul Surf April. 2007: 5(2):75. Osmolarity Tear hyperosmolarity may reasonably be regarded as the signature feature that characterizes h t i th the condition diti off ““ocular l surface f d dryness””1 Hyperosmolar levels in the tear film may transiently spike during tear instability, resulting g in corneal inflammation and triggering gg g sensory y neurons6 2009.10.02-CN1396 References: 1.Report of the International Dry Eye Workshop. Ocul Surf April. 2007: 5(2):119 6. Liu H. et al. A link between tear instability and hyperosmolarity in dry eye. Invest Ophthalmol Vis Sci. 2009 Aug;50(8):3671-9. Epub 2009 Mar 25 Population-based studies of dry eye1 *Different definitions of dry eye were used in each study. 2009.10.02-CN1396 Reference 1. Report of the International Dry Eye Workshop. Ocul Surf April. 2007: 5(2):95. 5 The tear film has 2 layers 2009.10.02-CN1396 The Lacrimal Apparatus Function: To optimise visual clarity • Produces tears • Produces tear film components • Drains D i away ttears 2009.10.02-CN1396 The Lacrimal Apparatus Lacrimal Apparatus • Principle and accessory (Kraus and Wolfring) lacrimal glands: produce tear fluid p • Goblet cells: secrete mucins • Meibomian glands: secrete lipids • Glands of Zeiss and Moll: secrete lipids 2009.10.02-CN1396 The 7 Functions of Tear Film 1)) Maintains hydration y of the eye y 2) Lubricates the ocular surface 3)) Nourishes the cornea 4) Cleanses the ocular surface 5) Defends against bacterial invasion 6) Buffers the pH of the ocular surface 7) Refracts light for visual clarity 2009.10.02-CN1396 Overview of Dry Eye Disease Dry feeling eyes presents in 2 forms that can occur together: • Evaporative dry eye: caused by increased evaporation of the tear film1 • Tear-deficient Tear deficient dry eye: caused by changes in the tears themselves1 Tear film instability can be caused by many things Environmental factors 2009.10.02-CN1396 Biological factors Reference 1. Report of the International Dry Eye Workshop. Ocul Surf April. 2007: 5(2):77 Causes of evaporative dry eye Photo courtesy of David W. Hansen, OD, FAAO Photo courtesy of David W. Hansen, OD, FAAO 2009.10.02-CN1396 Causes of Tear-Deficient Tear Deficient Dry Eye 2009.10.02-CN1396 Reference 1. Report of the International Dry Eye Workshop. Ocul Surf April. 2007: 5(2):99 Inflammation and Dryy Eye y Disease1 2009.10.02-CN1396 Reference 1. Report of the International Dry Eye Workshop. Ocul Surf April. 2007: 5(2):85 Slit Lamp Examination Photo courtesy of Elena Garcia Rubio, DOO 2009.10.02-CN1396 Test of Tear Function 1. Tear break up time (TBUT) • Fluorescein is placed onto the ocular surface • The time it takes for dark areas to form is measured • Normal: > 10 sec (Caucasian); > 5 sec (Asian) 2009.10.02-CN1396 Test of Tear Function 2. Schirmer’s test • Apply a paper strip to the lower and measure the amount of wetting occuring over a specific time-period (e.g. 5 minutes) • Schirmer I (without anesthesia); Schirmer II (with anesthesia) • Dry Eye? < 10 mm in 5 mins (Schirmer II) Schirmer’s Test 2009.10.02-CN1396 Test of Tear Function 3. Phenol Red Thread • A 70-mm thread impregnated with phenon red is inserted into the lowerlid for 15 seconds • Color changes from red to yellow when the thread absorbs the tears • Normal > 15 mm; dry eye < 9mm Phenol Red Thread 2009.10.02-CN1396 Test of Tear Function 4. Tears meniscus • Can be seen resting on the lower lid • A height of 0.3 mm is considered normal 2009.10.02-CN1396 Other parameters? Maximum blink interval (MBI) • Area of break-up (AB) Transient increases in tear hyperosmolarity during tear instability caused the sensations noted by subjects Ocular Surface Disease Index Management of underlying disorders Eyelid disorders can cause dry eye disease • Treatment of blepharitis (eyelid inflammation) E lid scrubs Eyelid b Antibacterial ointments Steroid drops p Photo courtesy of David W. Hansen, OD, FAAO • Treatment of ectropion or entropion Blepharoplasty Sjögren s dry eye patients are generally managed the Sjögren's same way as non-Sjögren’s Photo courtesy of David W. Hansen, OD, FAAO 2009.10.02-CN1396 Natural Therapies for Dry Eye Blinking • Frequent blinking helps spread the tear film evenly and combats evaporation Hydration • Dehydration can make dry eye symptoms worse Environmental changes • Use humidifier or air filter1 • Avoid fans1 • Take breaks from the computer1 • Change contact lenses or wear less frequently Dietary supplements • Omega 3 fatty acids1 2009.10.02-CN1396 Reference 1. Report of the International Dry Eye Workshop. Ocul Surf April. 2007: 5(2):173 Office Environment & Dry Eye Eye irritations in office environment? Prevalence & symptoms •5-40% reported with eye irritation symptoms in office buildings •symptoms include : – burning – dry – gritty – itchy – scratchy – sore – stinging – strained eyes Factors associated with eye irritations in office environments •Humidity •Room temperature •Indoor air velocity •VDU work •Contact lens wear •Makeup Low relative humidity •20% decrease of relative humidity will increase the rate of evaporation by 100% High room temperature •1ºC 1ºC d decrease iin room ttemperature t was associated i t d with ith 19% d decrease off reported eye symptoms Indoor air velocity •High horizontal or downward air velocity along the head region increases evaporation of water from the eye, eye causing dry eye symptoms VDU work – Task •Blink frequency during an active computer task with demand on vision and hand hand-eye eye coordination was 69% lower than during a passive task like watching a film on a VDU VDU work – Monitor position •The effect of lowering the gaze angle by 25º decreased ocular surface area byy 7% VDU work – Eyelid squint Relaxation After squint During squint •Squinting S i ti att a computer t screen may reduce d bli blink k frequency by half Makeup •There There is a significant association between the use of eye makeup and a thin li id llayer off th lipid the ttear fil film Female s using makeup •Oils in the eye makeup may be able to displace the phospholipids and influence the formation of lipid p layer y on the cornea Franck C. Fatty layer of the precorneal film in the “office eye syndrome”. Acta Ophthalmol (Copenh) 1991;69:737-743. Ways to reduce dry eye symptoms in office environments WORKSTATION 1 Relative 1. R l ti h humidity idit ffrom 40% - 60% 2. Lowering room temperature may reduce tear film evaporation. The optimal room oo temperature e pe a u e is s be between ee 20 0a and d 22ºC C 3. Avoid ventilation directed at your eyes 4. Adjust the position of the monitor. Downward gaze may minimize loss of water from the tear film 5. Change font and font size of character displayed on the monitor to avoid squinting i ti 6. Remove glare source to avoid squinting 7 Alt 7. Alternate t b between t work k with ith a high hi h and d llow d degree off visual i l and d cognitive iti demands p blinks help p restore 8. Microbreaks everyy 1-2 minute and exercise of complete normal tear film stability Basic ingredients of tear supplements • Water: replaces water loss • Buffer: maintains pH of the solution. Contains electrolytes • Active ingredient: A lubricant to reduce friction and/or a demulcent to sooth irritated membranes. Increases ocular l surface f retention t ti time. ti • Preservative: Used to prolong the shelf life. Can be toxic to the eye. y Not used in all formulations. 2009.10.02-CN1396 Eye drop strategies Increase retention times The main limitation of eye drops is their relatively short duration of action: they are effective only while they remain on the eye. The most common way to increase ocular retention is to increase viscosity, y, so manyy manufacturers add thickening agents. Newer viscoelastics formulations help to increase retention times without blurring. 2009.10.02-CN1396 Reference 1.Report of the International Dry Eye Workshop. Ocul Surf April. 2007: 5(2):87 Eye drop strategies Counteract hypertonicity The tears of dry eye sufferers have an increased osmolarity (the concentration of solutes in a solution) due to a hypertonic tear film1. The use of a hypotonic eye drop p may y address this p problem. Hypotonic yp p products include blink intensive tears, TheraTears and HypoTears. 2009.10.02-CN1396 Reference 1.Report of the International Dry Eye Workshop. Ocul Surf April. 2007: 5(2):87 Eye drop strategies Avoid older generation toxic preservatives It is i generally ll recognised i d that th t preservatives ti do d cause sensitivity, iti it especially i ll older ld 1 preservatives such as BAK . A preservative free solution would be the first choice. However, new generation ‘ ‘smart’ t’ preservatives ti such h as P Purite it or OcuPure O P preservative ti help h l combine bi th the best of both worlds. 2009.10.02-CN1396 Reference 1.Report of the International Dry Eye Workshop. Ocul Surf April. 2007: 5(2):165 Thank you for listening blink and Ocupure are trademarks owned by or licensed to Abbott Laboratories, its subsidiaries or affiliates. Systane y is a trademark of Alcon Laboratories Inc.;; Hyabak y is a trademark of Thea Laboratories;; THERA TEARS is a trademark of Advanced Vision Research Inc.; Hypotears is a trademark of Novartis Inc.; Optrex Actimist is a trademark of Reckitt Benckiser Ltd.; Purite is a trademark of Allergan Inc.. © 2009 Abbott Medical Optics Inc. 2009.10.02 – CN1396