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The corneal diseases are one of the leading causes of blindness in the world. in most cases, these infections are preventable or treatable.

This seminar provides an overview of the anatomy and physiology of the cornea, as well as an overview of common conditions.

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  2. 2. ‫الرحمن‬ ‫ا‬ ‫بسم‬ ‫الرحيم‬
  3. 3. introduction The corneal diseases are one of the leading causes of blindness in the world. in most cases, these infections are preventable or treatable. This seminar provides an overview of the anatomy and physiology of the cornea, as well as an overview of common conditions.
  4. 4. Anatomy The cornea is a highly specialised structure which possesses the following vital functions:  a clear refractive interface,  tensile strength,  and protection of the intraocular contents from the external environment. It has an elliptical shape with the dimensions 10.6 mm vertically and 11.7 mm horizontally
  5. 5. the cornea consists of five layers
  6. 6. 1 Epithelium : consisting of five or six layers of epithelial cells, which are continues with the conjunctival epithelium. The basement membrane is the innermost layer of the epithelium . The epithelium is the only layer of the cornea that regenerates following trauma.
  7. 7. 2 Bowman’s layer: a thin homogeneous layer which servesas a base for the epithelial anchoring system. Once destroyed, this layer is never replaced. Its absence indicates previous trauma or ulceration.
  8. 8. 3 Stroma: This comprises 90% of the cornea , and is composed of parallel connective tissue . 4 Descemet’s membrane: Athin elastic membrane possessing high tensile strength and containing proteoglycans and glycoproteins in addition to collagen.
  9. 9. 5 Endothelium: This comprises a single layer of endothelial cells, which are metabolically active, and their primary function is the control of stromal hydration. The endothelium elongates when damage.
  10. 10. Function of the Cornea The cornea shields the rest of the eye from dust, germs and other harmful foreign matter. It also controls and focuses incoming light but contains no blood vessels to nurture or protect it against infection. • Protection. • Refraction. • Transmission of light
  12. 12. BACTERIAL INFECTIONBACTERIAL INFECTION Most common microorganism/ • Staphylococci G+ - aureus - epidemidis • streptococci G+ - pneumoniae - pyogenes • Pseudomonas aeruginosa • Neisseria
  13. 13. Signs and symptoms  painful red eye with a localised abscess in the cornea accompanied by stromal ulceration should arouse clinical suspicion.  There may be an acute uveitis with hypopyon. Photophobia.
  14. 14. Diagnosis Clinical history. Physical examination. Cultures of corneal scrapings (for identification the organism) Corneal biopsy .
  15. 15. Treatment Hospitalization Topical administration (rout of choice) Subconjuntival injection . I.V antibiotic . Oral antibiotics (low efficacy)
  16. 16. FUNGALE INFECTIONFUNGALE INFECTION A fungal keratitis is an inflammation of the eye's cornea that results from infection by a fungal organism.
  17. 17. Symptoms of Fungal Keratitis Symptoms of fungal keratitis include: Eye pain and redness Blurred vision Sensitivity to light Excessive tearing or discharge If you experience any of these symptoms, remove your contact lenses (if you wear them) and call your eye doctor right away. Fungal keratitis is a very rare condition, but if left untreated, it can become serious and result in vision loss or blindness.
  18. 18. Riske factors Fungal keratitis most commonly occurs in tropical and sub-tropical regions of the world. In temperate areas of the world, risk factors for developing fungal keratitis include: Recent eye trauma. Underlying ocular (eye) disease. Weakened immune system. Contact lens use.
  19. 19. Fungal Keratitis Diagnosis History. Physical examination. culture from corneal scrapings is considered to be the standard for definitive diagnosis of fungal keratitis.
  20. 20. Fungal Keratitis
  21. 21. Treatment for Fungal Keratitis Fungal keratitis must be treated with prescription antifungal medicine for several months.  Natamycin is a topical ophthalmic antifungal medication that works well on superficial corneal infections, particularly those caused by filamentous fungi such as Aspergillus and Fusariumspecies.  However, corneal infections that are deeper and more severe usually require treatment with systemic antifungal medication such as amphotericin B, fluconazole, or voriconazole. Patients who do not get better after topical and oral antifungal medications may require surgery, including corneal transplantation.
  22. 22. VIRAL INFECTIONVIRAL INFECTION Herpes simplex Herpes zoster The DNA viruses, herpes simplex and herpes zoster, are the commonest viral infections of the cornea.
  23. 23. Herpes simplex Clinical presentation Primary infection usually in children, involving the eyelids and lips. Corneal involvement is rare. A minor follicular conjunctivitis may occur.
  24. 24. Recurrent infection 1 Acute stage: a unilateral painful red eye with superficial ulceration taking the form of club shaped finger-like processes (dendritic /dendritiform). Fluorescein stains the epithelial defect and Rose Bengal identifies dead epithelial cells along the edge of the defect.
  25. 25. 2 Chronic stage: the disease may progress to ulceration, scarring, or perforation.
  26. 26. Symptoms: • Red eye. • Pain. • Photophobia. • Epiphora (tearing). • History of previous episodes. • May complain of blurred vision.
  27. 27. Diagnosis Assess visual acuity. Examine lids and conjunctiva for evidence of inflammation. Involvement here is less common in secondary infection although conjunctival injection (red eye) is almost universal. There may be erosions around the lid margin with the presence of small vesicles or pustules. Observe cornea: any opacities or haziness? This may suggest stromal involvement. Test corneal sensation this can be reduced in epithelial disease. Stain the cornea and look for evidence of ulcers by staining with fluorescein.
  28. 28. Treatment  Antiviral medications including: acyclovir (the drug of choice ) trifluridine, vidarabine, and idoxuridine. Steroids in chronic oedema.  keratoplasty for perforations and scarring.
  29. 29. Herpes zoster The pathological features of herpes zoster infection of the cornea are very similar to those described for chronic.
  30. 30. PARASITIC INFECTIONPARASITIC INFECTION Various parasitic infections are important causes of ophthalmic diseases worldwide. Most parasitic infections are spread by insect vectors or consuming or getting contact with contaminated water
  31. 31. Various organisms producing keratitis are the following: Acanthamoeba Microsporidia Onchocerca Leishmania- Trypanosoma bruci
  32. 32. The pathogenic species of Acanthamoeba known to produce keratitis are the following 1. A castellani 2. A polyphaga 3. A hatchetti 4. A culberstoni 5. A rhysodes 6. A griffina
  33. 33. Acanthamoeba keratitis Acanthamoeba was first established as a case of human disease in 1973 This vision threatening corneal disease was first recognized in contact lens wearers. There was a sharp increase in the recognition(and perhaps incidence ) of this disease in the late 1980’s. First case of Acanthamoeba keratitis from India was reported in 1987 from Aravind Eye Hospital, Madurai
  34. 34. Clinical signs  are discussed in three stages 1. Early stage / Epithelial defects, epithelial haze pseudodendrites 2. Late stage / Epithelial defects, stromal infiltrates, nummular keratitis 3. Advanced stage/ Ring infiltrate, satellite lesions, stromal abscess
  35. 35. Other features - Severe anterior and posterior uveitis - Nodular or Diffuse scleritis - Corneal stromal infiltrates (single,multiple,ring shape) - Anterior uveitis (transient hypopyon) - Radial keratoneuritis - Disciform keratitis
  36. 36. Clinical characteristics that help to distinguish Acanthamoeba keratitis from other keratitis include the following: 1. Ring infiltrate 2. Elevated epithelial lesion 3. Relative lack of vascularisation even in chronic and severe cases
  37. 37. Treatment There is no consensus on treatment. Various regimens are described. Treatment is required for 6-12 months.  Prolonged medication results in corneal vascularisation and toxic keratitis.
  39. 39. Nursing Diagnosis for Corneal infiction a. Anxiety related to damage to sensory and lack of understanding of post-operative care, drug delivery. Nursing interventions: - Assess the degree and duration of visual impairment - Orient the patient to the new environment - Describe the routine perioperative - Encourage to perform daily living habits when able - Encourage the participation of the family or the people who matter in patient care.
  40. 40. b. Risk for Injury related to damage vision. Nursing interventions: - Help the patient when able to do until a stable postoperative ambulation - Orient the patient in the room - Discuss the need for the use of metal shields or goggles when necessary - Do not put pressure on the affected eye trauma - Use proper procedures when providing eye drugs
  41. 41. c. Acute Pain related to trauma, increased IOP, surgical intervention or administration of inflammatory eye drops dilator. Nursing interventions: - Give the medication to control pain and the IOP as prescribed - Give cold compress on demand for blunt trauma - Reduce lighting levels - Encourage use of sunglasses in strong light
  42. 42. d. Risk for self-care deficit related to damage vision. Nursing interventions: - Give instructions to the patient or the people closest to the signs and symptoms, complications should be immediately reported to the doctor. - Provide verbal and written instructions to patients and the right means of technique in delivering drugs - Evaluate the need for assistance after discharge - Teach patients and families of sight guidance techniques