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Trachoma. Acknowledgement. Materials from the WHO programme for prevention of blindness is used for this presentation. Introduction. Ocular infection with clamidia trachomatis serovars A,B,Ba and C Second leading cause of blindness worldwide
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Acknowledgement • Materials from the WHO programme for prevention of blindness is used for this presentation
Introduction • Ocular infection with clamidia trachomatis serovars A,B,Ba and C • Second leading cause of blindness worldwide • Disappearance in Europe and America predated antibiotics
Pathogenesis of trachoma blindness • Normal conjunctiva • Trachoma conjunctivitis and re-infection • Secondary bacterial infections • Scarring • Trichiasis • Corneal opacity • Blindness
Magnitude of the problem • 590 million people at risk from blinding trachoma • 150 million people have active trachoma • 10.6 million people have trichiasis • 5.9 million people blind from trachoma • 15% of global blindness: 2nd cause of blindness
Geographic distribution of blinding trachoma (Thylefors, 1995)
Distribution of disease • Trachoma is concentrated in hot, dusty, dry parts of the world. Proxy for poverty • Within endemic countries, trachoma is found in areas that are: • Rural • Economically underdeveloped • Without good water supplies • Without basic sanitation • Since it is an infectious disease, trachoma clusters at neighbourhood and household level
Intervention: SAFE strategy • Surgery for trichiasis • Antibiotics for TF/TI • Facial cleanliness to prevent transmission of C. trachomatis • Environmental change to prevent transmission of C. trachomatis
Transmission of Infection • Transmission of chlamydia from ocular and nasal secretion of children • Direct spread during play/sharing a bed • Conveyance on fingers • Indirect spread on fomites • Eye-seeking flies • Coughing/sneezing
Disruption of Infection cycle • Antibiotics • Faces, Fingers, Fomites and Flies: Hygiene • Environmental changes: • water provision and use • Overcrowded housing • Domestic waste management • Animal proximity to household
Which antibiotic? Tetracycline ointment b.d. for 6 weeks Cures 60-80% of cases of TF/TI if full course is administered; compliance a problem
Which antibiotic? Oral azithromycin More effective than tetracycline in normal programme conditions
Role of Optometrists • Training • Education • Community diagnosis • Refraction/correction • Low vision aids