Dry eye

Dry eye

1. DRY EYE DR K HARIPRIYA

2. Definition Dry eye is a multifactorial 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.

3. Tear film

4. Introduction Dry eye is recognized as a disturbance of the Lacrimal Functional Unit (LFU), an integrated system comprising the lacrimal glands, ocular surface (cornea, conjunctiva and meibomian glands) and lids, and the sensory and motor nerves that connect them

5. This functional unit controls the major components of the tear film and responds to environmental , endocrinological and cortical influences. Its overall function is to - preserve the integrity of the tear film, -transparency of the cornea, - quality of the image projected onto the retina

6. Trigeminal sensory fibers arising from the ocular surface run to the superior salivary nucleus in the pons , efferent fibers pass nervus intermedius pterygopalatine ganglion . Here, postganglionic fibers arise, which terminate in the lacrimal gland, nasopharynx , and vessels of the orbit.

7. Another neural pathway controls the blink reflex, via trigeminal afferents and the somatic efferent fibers of the seventh cranial nerve.

8. SSWS

9. Effect of environment Milleu interior Low blink rate ,aging Wide lid aperture Low androgen pool Systemic drugs Milleu exteror Low relative humidity High wind velocity Occupational environment

10. Aqueous Tear-Deficient Dry Eye (Tear Deficient Dry Eye; Lacrimal Tear Deficiency) Sjogren syndrome: It is an exocrinopathy in which the lacrimal and salivary glands are targeted by an autoimmune process. The lacrimal and salivary glands are infiltrated by activated T-cells, which cause acinar and ductular cell death and hyposecretion of the tears or saliva. Inflammatory activation within the glands leads to the expression of autoantigens at the surface of epithelial cells

11. Sjogrens syndrome The precise triggers leading to autoimmune acinar damage are not known in full, but risk factors include genetic profile, androgen status, and exposure to environmental agents, ranging from viral infections affecting the lacrimal gland to polluted environments. A nutritional deficiency in omega-3- and other unsaturated fatty acids has been reported in patients with SS

12. Sjogrens syndrome Two types Primary SS consists of the occurrence of ADDE in combination with symptoms of dry mouth Secondary SS consists of the features of primary SS together with the features of an overt autoimmune connective disease, such as rheumatoid arthritis, SLE, etc..

13. Non- Sjogren Syndrome Dry Eye Primary lacrimal gland deficiencies: Age-related dry eye Congenital alacrima Familial dysautonomia

14. Age-related dry eye Ductal pathology Peri ductal , inter acinar fibrosis Paraductal blood vessel loss Acinar atrophy Low grade dacryoadenitis

15. Congenital Alacrima rare cause of dry eye in youth. It is also part of certain syndromes, triple A syndrome Protien ALLADIN

16. Familial dysautonomia Developmental , progressive neuronal abnormality of the cervical sympathetic and parasympathetic innervations of the lacrimal gland and a defective sensory innervation of the ocular surface Generalized insensitivity to pain is accompanied by a marked lack of both emotional and reflex tearing,

17. NSDE Secondary lacrimal gland deficiencies Lacrimal gland infiltration Sarcoidosis Lymphoma AIDS Lacrimal gland ablation Lacrimal gland denervation

18. NSDE Obstruction of the lacrimal gland ducts: Trachoma Cicatricial pemphigoid and mucous membrane pemphigoid Erythema multiforme Chemical and thermal burns

19. NSDE Reflex hyposecretion Reflex sensory block Contact lens wear Diabetes Neurotrophic keratitis Reflex motor block Cranial nerve damage Multiple neuromatosis Exposure to systemic drugs

20. Evoperative dry eye Intrinsic causes MGD Disorders of lid aperture Low blink rate

21. Extrinsic causes: Occular surface disorders Vitamin A Deficiency Topical Drugs and Preservatives Allergic conjunctivitis

22. Inspection Signs of associaed systemic diseases Indications of personnel habits Ocular disease(lid malposition )

23. Evaluation of tear film Tear meniscus height TBUT Meniscometry : Tear meniscus radius, height and cross sectional area 1MM, CONVEX-NORMAL <0.3 MM IS abnormal Tear film lipid layer interferometry color comparison table kinetic analysis

24. TESTS OF TEAR PRODUCTION SCHIRMER TEST BASIC SCHIRMER 1 SCHIRMER 11 Inference - > 15 mm - normal, 6 to 10 mm - borderline dry, < 6 mm - impaired secretion.

25. Tear composition assays Tear Osmolarity

26. Rose Bengal staining – The dye has an affinity for dead or devitalized epithelial cells and for areas devoid of mucus. Van Bijsterveld scoring system – divide the ocular surface into three zones: • Nasal bulbar conjunctiva , Cornea Temporal bulbar conjunctiva. Each zone is then given a score of ‘0’ (no stain) to ‘3’ (confluent stain). Scores in each eye is totaled. A score of 3.5 or greater indicates positive for keratoconjunctivitis

27. Newer technologies MEIBO METRY Casual Lipid level (expressed as arbitrary optical density units) is calculated as (C-B), where C is the casual reading, B is the reading from the untouched tape MEIBO GRAPHY /MEIBO SCOPY Finoff transilluminator Most reliable test in patients with ectodermal dysplasia syndrome

28. Brush Cytology Technique 1) squamous metaplasia , 2) detecting inflammatory cells 3) expression of several surface markers on the ocular surface epithelium Flow cytometry in impression cytology HLA DR expression by epithelial cells, gold standard for inflammatory assesment

29. Ferning Test (TFT ) TO DIAGNOSE Quality of tears (electrolyte concentration), KCS, Hyperosmolarity The patterns of crystallization ( ferning ) are classified in 4 classes: Type 1: uniform large arborization , Type 2: ferning abundant but of smaller size; Type 3: partially present incomplete ferning ; Type 4: no ferning . Types 1 & 2 are reported to be normal and Types 3 & 4 reported to be abnormal

30. Fluorophotometry ( Fluorimetry ) Tear Function Index TFI is the quotient of the Schirmer test value and the Tear clearance rate (TCR). A TFI of less than 40 is 100% sensitive for patients with SS dry eye

31. MANAGEMENT A. Tear supplementation: lubricants B. Tear Retention C. Tear stimulation: secretagogues D. Biological tear substitutes E. Anti-inflammatory therapy F. Essential fatty acids G. Environmental strategies

32. A. Tear supplementation: lubricants Hypotonic or isotonic buffered solutions containing electrolytes, surfactants, and various types of viscosity agents. Ideal artificial lubricant should be preservative-free, contain potassium, bicarbonate, and other electrolytes and have a polymeric system to increase its retention time. Physical properties Neutral to slightly alkaline pH. Osmolarities 181 to 354 mOsm /L.

33. Tear supplementation: lubricants Electrolytes potassium, bicarbonate Osmolarity Viscosity agents: prolong ocular surface contact, increasing the duration of action and penetration of the drug Eye ointments and gels

34. B. Tear Retention 1. Punctal Occlusion Types absorbable and nonabsorbable . The former are made of collagen or polymers and last for variable periods of time (3 days-6 mnths ). The nonabsorbable “permanent” plugs include silicon plugs, consists of a surface collar resting on the punctal opening, a neck, and a wider base Herrick plug is shaped like a golf tee and is designed to reside within the canaliculus . cylindrical Smart plug: expands and increases in diameter in situ, due to thermodynamic properties of its hydrophilic acrylic composition.

35. Punctal Occlusion Indications patients who are symptomatic of dry eyes have a Schirmer test (with anesthesia) result less than 5 mm at 5 minutes, and show evidence of ocular surface dye staining

36. Contra indications Allergy to the materials used in the plugs to be implanted, punctal ectropion , pre-existing nasolacrimal duct obstruction, clinical ocular surface inflammation,

37. Complications Extrusion Internal migration of a plug, Biofilm formation Infection pyogenic granuloma formation

38. Tear Retention Moiature chamber spectacles Contact lenses

39. Tear Stimulation: Secretogogues Diquafosol Rebamipide Gefarnate Ecabet sodium

40. D. Biological Tear Substitutes Serum Salivary Gland Autotransplantation : Indicated only in end-stage dry eye disease with an absolute aqueous tear deficiency ( Schirmer -test wetting of 1 mm or less), a conjunctivalized surface epithelium persistent severe pain despite punctal occlusion and at least hourly application of unpreserved tear substitutes.

41. Due to the hypoosmolarity of saliva, compared to tears, excessive salivary tearing can induce a microcystic corneal edema, which is temporary, but can lead to epithelial defects.

42. E. Anti-Inflammatory Therapy 1. Cyclosporine 2. Corticosteroids 3. Tetracyclines a. Properties of tetracyclines and their derivatives 1) Antibacterial properties 2) Anti-inflammatory 3) Anti- angiogenic properties

43. Essential fatty acids Environmental strategies: Use of room humidifiers Avoid extreme/harsh environmental conditions.

44. Treatment recommendations by severity level Level 1: Education and environmental/dietary modifications Elimination of offending systemic medications Artificial tear substitutes, gels/ointments Eye lid therapy Level 2: Anti- inflammatories Tetracyclines (for meibomianitis , rosacea ) Punctal plugs , Secretogogues Moisture chamber spectacles

45. Treatment recommendations by severity level Level 3: Serum Contact lenses Permanent punctal occlusion Level 4: Systemic anti-inflammatory agents Surgery (lid surgery, tarsorrhaphy ; mucus membrane, salivary gland, amniotic membrane transplantation)

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