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Geographic variations in microbial keratitis: an analysis of the peer-reviewed literature
  1. Ameet Shah1,
  2. Arun Sachdev2,
  3. David Coggon3,
  4. Parwez Hossain4
  1. 1Moorfields Eye Hospital, London, UK
  2. 2St Paul's Eye Unit, Royal Liverpool University Hospital, Liverpool, UK
  3. 3MRC Epidemiology Resource Centre, University of Southampton, Southampton, UK
  4. 4Division of Infection, Inflammation & Immunity, University of Southampton, Southampton General Hospital, Southampton, UK
  1. Correspondence to Mr Parwez Hossain, Division of Infection, Inflammation & Immunity, Eye Unit, University of Southampton, Southampton General Hospital, Tremona Road, Southampton SO16 6YD, UK; parwez{at}


The epidemiology of microbial keratitis has been investigated in several studies by analysis of organisms cultured from corneal scrapes. However, a comparison of the frequency of different organisms causing keratitis in different parts of the world is lacking. The authors present a review incorporating an analysis of data from studies worldwide. The data provide a comparison of the frequency of culture-positive organisms found in different parts of the world. Associations between a country's gross national income and types of causative organism are explored. The highest proportion of bacterial corneal ulcers was reported in studies from North America, Australia, The Netherlands and Singapore. The highest proportion of staphylococcal ulcers was found in a study from Paraguay, while the highest proportion of pseudomonas ulcers was reported in a study from Bangkok. The highest proportions of fungal infections were found in studies from India and Nepal. The Spearman correlation coefficient demonstrated statistically significant correlations between gross national income and percentages of bacterial (0.85 (95% CI 0.68 to 0.91, p<0.0001)), fungal (–0.81 (95% CI −0.90 to −0.66, p<0.0001)) and streptococcal (−0.43 (95% CI −0.66 to −0.12, p=0.009)) isolates.

  • Cornea
  • keratitis
  • corneal ulcer
  • infection
  • epidemiology
  • public health
  • epidemiology
  • microbiology

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  • Competing interests None.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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