Cornea and ocular surface anatomy and physiology

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  • 1.Cornea and Ocular Surface Anatomy, Physiology and Immunology Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com

2. Why is there a cake on this slide? Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 3. Lamellar Structure - Cornea Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 4. Tear film Structure Function Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 5. Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 6. Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 7. Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 8. Conjunctiva Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 9. Conjunctiva anatomy 1. Epithelium 2. Substantia propria (vascular stroma) a) Lymphoid layer (superficial) b) Fibrous layer (deep) Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 10. Conjunctiva anatomy Substantia propria layers a) lymphoid layer Superficial, thin Diffusely distributed lymphocytes Contain mast cells b) fibrous layer Deep, thicker Contains vessels, lymphatics and nerves Attachments: tarsal plate & limbus Mast cells: predominantly in perilimbal & tarsal lymphoid layer Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 11. Cornea Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 12. Corneal Anatomy and Physiology The cornea is a transparent, avascular structure. It consists of 5 layers : A Anterior Epithelium: Non-keratinised stratified squamous epithelium. Cells migrate from the basal layer upwards and from the periphery to the centre. Barrier and optical function. Tear film. B Bowman's membrane condensed stroma - structural C Stroma: Connective tissue layer, type 1 collagen. Keratocytes (fibroblasts). Anterior compact, posterior spongy. D Descemet's Membrane barrier E Endothelium: Actively pumps water and ions from the stroma to produce corneal dehydration and transparency. If damaged, these cells do not regenerate (can slide) and corneal decompensation occurs where the cornea becomes white and cloudy Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 13. Confocal microscopy Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 14. Figure 1. Heidelberg Retina Tomograph 2 Rostock Cornea Module confocal images of central cornea (23-year-old woman) showing (A) an epithelial wing cell layer, (B) an epithelial basal cell layer below the epithelial wing cell layer, and (C) less reflective fibrous structures at the level of Bowmans layer compared with subbasal nerves (arrowheads). In some images, the structures appear to form nodes (arrow). DF, Images of the polymorphic structures (K-structures; arrows) with subbasal nerve plexus (arrowheads). Dark shadows always accompany these fibers. These structures are 5 to 15 m in diameter and appear to consist of bundles of filaments. Bars, 100 m. Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 15. Epithelium Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 16. Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 17. Limbus Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 18. Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 19. Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 20. Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 21. Immunology Langerhans cells in epithelium = macrophages (antigen presenting cells APCs) Present Ag to lymphocytes Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 22. Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 23. Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 24. Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 25. Bowmans Structure Function Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 26. Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 27. Stroma Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 28. Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 29. Ultrastructure - collagen Collagen triple helix with crosslinks form microfibrils Collagen microfibrils lined up and cross- linked form collagen fibrils Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 30. Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 31. Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 32. (A) SEM of an adult human corneal keratocyte (K) showing the complex dendritic morphology of the cell body and processes. (B) Light micrographs of keratocyte network in the feline. Keratocytes are connected by broad cellular processes (open arrows) extending from main cell body which contains nucleus (arrows). Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 33. Corneal Innervation Trigeminal nerve (CN V) - Ophthalmic Branch (CN V1) - Long Ciliary nerves Sub epithelial nerve plexus Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 34. Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 35. (A) A stromal nerve surrounded by a keratocyte in a keratoconus patient. (B,C) CGRP positive nerve fibres in the subbasal plexus. (D,F) SP positive nerve fibres. Penetration of a stromal nerve fibre bundle through the Bowman's layer () and establishment of nerve leashes of the subbasal plexus is shown in (B) (arrows). The whole mount preparation shown in (C) illustrates the parallel running CGRP-positive nerve bundles of the subbasal plexus. The cross section in (D) illustrates SP-immunoreactive nerve fibre bundles in a 60 m thick frozen section. Tangential view of SP-positive beaded intraepithelial nerve terminals are shown in a whole mount preparation (F). (E) Schematic drawing on the architecture of nerve bundles in the subbasal plexus (arrow) containing a mixed population of straight and beaded fibres. Only the beaded fibres bifurcate from the bundle and turn upwards into the epithelium. Bar: A, 1 m; B; 25 m; C, 1 mm; D, 25 m; F, 10 m. Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 36. Subbasal nerve plexus in a 6 mm diameter central button from a 61 year-old left cornea. For clarity, only the largest diameter subbasal nerve fibers have been illustrated. Individual subbasal nerves follow straight or curvilinear trajectories and converge on an imaginary center, or vortex (asterisk), located approximately 2.5 mm inferonasal to the corneal apex. Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 37. Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 38. Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 39. What conditions are associated with corneal hypoaesthesia? HSV HZO Stroke/CVA Orbital tumours / trauma / surgery Chronic corneal inflammation and scarring Corneal surgery / trauma / contact lens PRP Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 40. Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 41. Dry eye/neurotrophic keratitis in a patient, who underwent an uneventful LASIK procedure 5 days earlier. The patient was treated with topical lubricants and wetting agents, and recovered completely. A:fluorescein staining reveals confluent epithelial surface lesions. The flap margins can also be observed. B: biomicroscopical image on the same eye. Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 42. Descemets Membrane Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 43. Endothelium Structure Function Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 44. Endothelial Pump Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 45. Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 46. Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 47. Pathology Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com 48. Corneal infections. A. Slit-lamp photograph of the cornea with Acanthamoeba keratitis. Subepithelial opacities and numerous radial keratoneuritis lesions. B. In the epithelial basal cell layer, numerous highly reflective, high-contrast round-shaped particles 10-20m in diameter suggestive of Acanthamoeba cysts were detected by in vivo laser confocal microscopy. (Bar=50m) C. Direct examination of the epithelial scraping with Parker ink-potassium hydroxide shows Acanthamoeba cysts. Note that the cysts have double walls with characteristic wrinkled outer wall. (Bar=10m) D. Slit-lamp photograph of the cornea with Aspergillus keratitis. Severe corneal ulcer was observed. E. In the stormal layer, numerous highly reflective, high-contrast branching filaments suggestive of Aspergillus hyphae were detected by in vivo laser confocal microscopy. (Bar=50m) F. scrapingrevealed Aspergillushyphae Dr Laurie Sullivan 2013 laurence.sullivan@gmnail.com

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