Inflammation of cornea

keratitis

1. INFLAMATION OF CORNEA OPTOM FASLU MUHAMMED

2. Inflammation of the cornea (keratitis) is characterized by corneal oedema, cellular infiltration and ciliary congestion. It is defined as a complex vascular response that results in the accumulation of the cellular exudates

3. KERATITIS - central Superficial , deep - non ulcerative , ulcerative Peripheral Superficial , deep - non ulcerative , ulcerative

4. Corneal ulcer Localized necrosis of sup. Stroma with destruction of overlying epithelium corneal ulcer may develop when: either the local ocular defence mechanism is jeopardized, or there is some local ocular predisposing disease, or host's immunity is compromised the causative organism is very virulent

5. 1. Corneal epithelial damage Corneal abrasion due to small foreign body, Epithelial drying as in xerosis and exposure keratitis. Necrosis of epithelium Epithelial damage due to tropic changes as in neuroparalytic keratitis.

6. Causative organisms. Common bacteria associated with corneal ulceration are: Staphylococcus aureus, Pseudomonas pyocyanea, Streptococcus pneumoniae, E. coli, Proteus, Klebsiella, N. gonorrhea, N. meningitidis and C. diphtheria.

7. Pathology of localized corneal ulcer 1. Stage of progressive infiltration infiltration of polymorph nuclear and/or lymphocytes into the epithelium from the peripheral circulation supplemented by similar cells from the underlying stroma if this tissue is also affected

8. 2. Stage of active ulceration Active ulceration results from necrosis and sloughing of the epithelium, Bowman's membrane and the involved stroma.

9. 3. Stage of regression Regression is induced by the natural host defence mechanisms A line of demarcation develops around the ulcer, which consists of leucocytes that neutralize and eventually phagocytes the offending organisms and necrotic cellular debris

10. 4.Stage of cicatrization In this stage healing continues by progressive epithelization which forms a permanent covering. When ulcer involves Bowman's membrane and few superficial stromal lamellae, the resultant scar is called a 'nebula‘ Macula – one third leucoma – more than one third of stroma