Cornea Sclera DR KHALID AL ZUBI ASSOCIATE PROFESSOR

Cornea & Sclera DR KHALID AL ZUBI ASSOCIATE PROFESSOR SPECIAL SURGERY DEPARTMENT FACULTY OF MEDICINE-MUTAH UNIVERSITY 1

Gross anatomy 2

Microscopic Anatomy 3

Anatomy � Five layers � Function and role of collagen fibers compaction (regular arrangement, avascularity and dehydration) � Functions: major refractive surface, protection of intraocular contents � Thickness & diameters: CCT 0. 55 mm, average diameter 11 -12 mm. � Nutrition: perilimbal vessels, aqueous humor and atmospheric air for oxygen. 4

Infective corneal disorders � Viral keratitis : Herpes simplex Herpes Zoster � Bacterial keratitis � Fungal keratitis � Acanthamoeba keratitis 5

Herpes Simplex Keratitis � Type 1 HSV is the important cause of ocular symptoms. � Type 2 HSV is more common to cause genital disease but can cause keratitis and chorioretinitis in infants. � Infection can be : primary secondary 6

HSV keratitis Primary � As a viral infection it is associated with fever . � Vesicular rash � Follicular conjunctivitis. � Pre-auricular lymphadenopathy. � And can be asymptomatic. � Corneal involvement is usually with punctate epithelial damage , and may not be involved. 7

HSV keratitis Secondary � Recurrent infections results from reactivation of the dormant virus in the dorsal root ganglion and her in the trigeminal ganglion. � Virus travels down in the nerves till it reaches the final structures as the cornea. � Usually occurs in a debilitated patients 8

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HSV keratitis Secondary � Dendritic epithelial ulcers usually heals without scars. � Stromal involvement : can lead to edema and scaring that may require PKP � Uveitis � Disciform keratitis : which is thought to be an immunological reaction to the virus antigens (no epithelial ulceration). � Necrotizing stromal keratitis: rare, stromal necrosis and melting, ant. Uveitis and corneal scarring. 1 0

HSV treatment �Topical anti-virals as : Acyclovir (zovirax ) Idoxuridine Vidarabine Triflurothymidine �Avoid topical steroids if epithelial ulcer is present. �Stromal keratitis needs cautious steroid use. 1 1

Herpes Zoster Ophthalmicus � Caused by varicella –zoster virus the cause of chickenpox � The ophthalmic division of the trigeminal nerve is involved. � Ocular involvement is higher if the nasociliary branch of the nerve is involved (hutchinson sign). � Usually there is a prodromal phase and the patient is unwell. 1 2

HZO ophthalmic manifestations �Usually preceded by maculopapular rash then vesicular rash at the area of the trigeminal distribution �Lid swelling �Keratitis �Iritis �Secondary glaucoma 1 3

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HZO treatment �Systemic antiviral will reduce the chance of post-herpetic neuralgia. �Topical steroids and antiviral �Glaucoma treatment if it occurred. �Both HSV & HZO will cause corneal anesthesia 1 6

Bacterial keratitis: Protective factors of the cornea � Blinking � Tears washing the debris � FB entrapment by mucus � Antimicrobial effect of the tears. � Epithelium protective mechanism 1 7

Predisposing factors for bacterial keratitis �Dry eye �Epithelial disturbance �Contact lens wear �Prolonged use of steroids 1 8

Causative Bacteria �Staph . Epidermidis �Staph. Aurous �Strep. pneumonia �Coliforms �Pseudomonas �Haemophilus 1 9

Bacterial Keratitis symptoms &signs �Severe pain �Redness �Purulent discharge �Ciliary injection �Visual impairment �Corneal infiltrate �Hypopyon 2 0

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Bacterial keratitis management � Culture & sensitivity � Corneal scrape � Gram stain � Intensive topical AB � If complications as corneal perforation happen it may needs tissue adhesives and sometimes urgent grafting. 2 2

Acanthamoeba Keratitis �A freshwater amoeba is the causative factor. � Increased incidence in swimming with contact lenses � Very painful keratitis � Non-nutrient agar with E-coli. � Treatment with chlorhexidine & polyhexamethelene biguanide � Grafting may be required 2 3

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Fungal Keratitis � More common in worm climates � Suspect it when : No response to antibacterial treatment History of vegetable matter trauma Prolonged use of steroids � The corneal opacity is fluffy and satellite lesions may be seen. � Special (sabouraud agar) & prolonged cultures � Treatment with topical and systemic anti fungals 2 5

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Corneal dystrophies �Rare inherited disorders �Usually bilateral �Non-inflammatory �They can be : Anterior Stromal Posterior Treatment: symptomatic to corneal graft. 2 7

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Corneal shape disorders � Keratoconus : a form of corneal ectasia that results in central corneal thinning and different degrees of astigmatism � Usually painless and progressive � May be associated with ocular & systemic diseases. � Keratoglobus � Pellucid marginal degeneration � Treatment : cxlinking then we can treat the refractive errors. 2 9

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Central corneal degenerations �Band keratopathy : subepithelial deposition of calcium in the exposed part of the cornea due to the lower CO 2 and higher p. H. 3 1

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Band keratopathy associations �Hypercalcemia �Chronic intraocular inflammation �Glaucoma 3 3

Band keratopathy presentation and treatment �Discomfort �Visual loss �Treated by chemical chelation or excimer laser 3 4

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Peripheral corneal degenerations �Mooren”s ulcer : immunological painful peripheral corneal thinning. �Connective tissue disease associated as RA &WG. �Treatment requires immunosuppressive agents. 3 6

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Arcus senilis �A lipid deposition that is separated from the limbus by clear cornea. . �It may be a sign of hyperlipidemia (in young people). �Usually no treatment is needed. 3 8

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Corneal Grafting (PKP, lamellar keratoplasty) �Indications : Restore corneal clarity Removal of infected cornea Restore corneal regularity Refractive causes Cosmatic �Highly privileged avascular tissue �HLA typing may help to increase success rate. 4 0

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Corneal grafting technique � Recipient preparation � Donor preparation � Suturing � Follow up � Complication & treatment. Rejection Graft Failure Glaucoma High astigmatism 4 3

Refractive surgeries �Photorefractive keratectomy (PRK) �Laser epithelial keratomileusis (LASEK) �Laser in situ keratomileusis (LASIK) �Clear lens extraction and IOL implantation. �Smile surgery. �Corneal grafting. 4 4

Episcleritis �Inflammation of the episclera , the superficial layer of the sclera �Rarely associated with systemic diseases �Usually cause mild discomfort �Self limiting and may respond to topical anti -inflammatory agents. 4 5

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Scleritis �More serious and severe disease �Usually associated with connective tissue diseases as RA �Can be ischemic and inflammatory �Usually shows a swollen red areas that can be diffuse or focal �Can be anterior and posterior. 4 7

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Scleritis complications �Scleromalacia �Keratitis ( thinning of the sclera ) �Uveitis �Cataract �Glaucoma 5 0

Scleritis treatment �High dose steroids �Immunosuppressive agents. �Treatment of complications. 5 1

� Thank you. 5 2